Re: how does compaction_throughput_kb_per_sec affect disk io?

I would think that compaction_throughput_kb_per_sec does have indirect impact on disk IO. High number means or setting it to 0 means there is no throttling on how much IO is being performed. Wouldn't it impact normal reads from disk during the time when disk IO or util is high which compaction is t

Re: LevelDB type compaction

Can someone please help me understand this a little bit? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/LevelDB-type-compaction-tp6798334p6822344.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.

Re: LevelDB type compaction

> >> and updates could be scattered all over >> before compaction? > > No, updates to a given row will be still be in a single sstable. > > Can you please explain little more? You mean that if Level 1 file contains range from 1-100 all the updates would still go in that file? The link on le

Re: [BETA RELEASE] Apache Cassandra 1.0.0-beta1 released

This is a great new! Is it possible to do a write-up of main changes like "Leveldb" and explain it a little bit. I get lost reading JIRA and sometimes is difficult to follow the thread. It looks like there are some major changes in this release. -- View this message in context: http://cassandra-

Re: Is Cassandra suitable for this use case?

Ruby Stevenson wrote: > > hi Sasha - > > Yes indeed. this solution was in the second part of my original > question - it just seems "out of norm" on what people usually use > Cassandra for, I guess I am looking for some reassurance before I roll > up the sleeve of trying it. > > Thanks > > Rub

Re: 4/20 nodes get disproportionate amount of mutations

Thanks for the update Jeremy Hanna wrote: > > It appears though that when choosing the non-local replicas, it looks for > the next token in the ring of the same rack and the next token of a > different rack (depending on which it is looking for). Can you please explain this little more? -- V

Re: no stack trace :(

Are you seeing lot of these errors? Can you try XX:-OmitStackTraceInFastThrow -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/no-stack-trace-tp6654590p6657485.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.c

Re: move one node for load re-balancing then it status stuck at "Leaving"

Check things like netstats, disk space etc to see why it's in Leaving state. Anything in the logs that shows Leaving? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/move-one-node-for-load-re-balancing-then-it-status-stuck-at-Leaving-tp6655168p665

Re: Question about eventually consistent in Cassandra

What happens when DC is in different time zone so 9:00 pacific vs 11:00 Central -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Question-about-eventually-consistent-in-Cassandra-tp6646430p6649490.html Sent from the cassandra-u...@incubator.apache.

Re: how to solve one node is in heavy load in unbalanced cluster

springrider wrote: > > is that okay to do nodetool move before a completely repair? > > using this equation? > def tokens(nodes): > >- for x in xrange(nodes): > - print 2 ** 127 / nodes * x > Yes use that logic to get the tokens. I think it's safe to run move first and reair later.

Re: Brisk and Hadoop question

I think so to that Brisk may require all the nodes to be upgraded to Brisk. Are there any detailed instructions about how to configure cassandra with hadoop? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Brisk-and-Hadoop-question-tp6638681p6639

Re: how to solve one node is in heavy load in unbalanced cluster

First run nodetool move and then you can run nodetool repair. Before you run nodetool move you will need to determine tokens that each node will be responsible for. Then use that token to perform move. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.c

Re: Can we store java objects and images/files in cassandra

CASSANDRA learner wrote: > > Hi, > > Can we store images , java objects, files in cassandra, if so , how > Please let me know this as i need it urgently... > Look at http://goo.gl/S2E3C http://goo.gl/S2E3C It really depends on your workload. With heavy workloads cassandra is not the rig

Re: How are column sort handled?

Thanks! Then does it mean that before compaction if read call comes for that key sort is done at the read time since column b, c and a are in different ssTables. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/How-are-column-sort-handled-tp6595415

How are column sort handled?

Trying to understand the overhead when multiple columns are spread accross ssTables. For eg: Key K1 column b and c are in ssTable 1 and column a in ssTable 2. As I understand columns in a given row are sorted at the time it's stored. So does it mean that when "a" goes to ssTable 2 it also fetches c

Re: commitlog replay missing data

Peter Schuller wrote: > >> Recently upgraded to 0.8.1 and noticed what seems to be missing data >> after a >> commitlog replay on a single-node cluster. I start the node, insert a >> bunch >> of stuff (~600MB), stop it, and restart it. There are log messages > > If you stop by a kill, make sure

Re: Cassandra Capistrano recipes

try nohup -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Cassandra-Capistrano-recipes-tp6556591p6556636.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.

Re: RAID or no RAID

aaron morton wrote: > >> Not sure what the intended purpose is, but we've mostly used it as an >> emergency disk-capacity-increase option > > Thats what I've used it for. > > Cheers > How does compaction work in terms of utilizing multiple data dirs? Also, is there a reference on wiki somew

Re: RAID or no RAID

I thought there is an option to give multiple data dirs in cassandra.yaml. What's the purpose of that? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/RAID-or-no-RAID-tp6522904p6523523.html Sent from the cassandra-u...@incubator.apache.org mailing

RAID or no RAID

Which one is preferred RAID0 or spreading data files accross various disks on the same node? I like RAID0 but what would be the most convincing argument to put additional RAID controller card in the machine? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.na

How to create data model from RDBMS ERD

How should one go about creating a data model from RDBMS ER into Big Table Data model? For eg: RDBMS has many indexes required for queries and I think this is the most important aspect when desiging the data model in Big Table. I was initially planning to denormalize into one CF and use secondary

Re: Is LOCAL_QUORUM as strong as QUORUM?

Well it depends on the requirements. If you use any combination of CL with EACH_QUORUM it means you are accepting the fact that you are ok if one of the DC is down. And in your scenario you care more about DCs being consistent even if writes were to fail. Also you are ok with network latency. I th

Re: Is LOCAL_QUORUM as strong as QUORUM?

LOCAL_QUORUM gurantees consistency in the local data center only. Other replica nodes in the same DC and other DC not part of the QUORUM will be eventually consistent. If you want to ensure consistency accross DCs you can use EACH_QUORUM but keep in mind the latency involved assuming DCs are not lo

Re: 99.999% uptime - Operations Best Practices?

Les Hazlewood wrote: > > I have architected, built and been responsible for systems that support > 4-5 > 9s for years. > So have most of us. But probably by now it should be clear that no technology can provide concrete recommendations. They can only provide what might be helpful which varies

Re: 99.999% uptime - Operations Best Practices?

Start with reading comments on cassandra.yaml and http://wiki.apache.org/cassandra/Operations http://wiki.apache.org/cassandra/Operations As far as I know there is no comprehensive list for performance tuning. More specifically common setting applicable to everyone. For most part issues revolve

Re: 99.999% uptime - Operations Best Practices?

In my opinion 5 9s don't matter. It's the number of impacted customers. You might be down during peak for 5 mts causing 1000s of customer turn aways while you might be down during night causing only few customer turn aways. There is no magic bullet. It's all about learning and improving. You will

Re: Storing files in blob into Cassandra

Speaking purely from my personal experience, I haven't found cassandra optimal for storing big fat rows. Even if it is only 100s of KB I didn't find cassandra suitable for it. In my case I am looking at 400 writes + 400 reads per sec and grow 20%-30% every ear with file sizes from 70k-300k. What I

Re: Direct control over where data is stored?

Khanh Nguyen wrote: > > Is there a way to tell where a piece of data is stored in a cluster? > For example, can I tell if LastNameColumn['A'] is stored at node 1 in > the ring? > I have not used it but you can see getNaturalEndpoints in jmx. It will tell you which nodes are responsible for a gi

Re: Direct control over where data is stored?

Please give more detailed info about what exactly you are worried about or trying to solve. Please take a step back and look at cassandra's architecture again and what it's trying to solve. It's a distributed database so if you do what you are describing there is a potential of getting hotspots. W

Re: Reading quorum

Fredrik Stigbäck wrote: > > Does reading quorum mean only waiting for quorum respones or does it mean > quorum respones with same latest timestamp? > > Regards > /Fredrik > Well it depends on how your CL is for writes. If you write with QUORUM and then read with QUORUM then yes you will get at

Re: EC2 node adding trouble

Can you post the output of "netstat -anp|grep "LISTEN"|grep java" from all the 3 nodes? Also compare seconds nodes yaml with new nodes yaml and see what diff. you find, if any. Another thing try telnet tests from seed node to the new node. -- View this message in context: http://cassandra-user-

Re: Exception when starting

In this case, yes. I was asking for the cases where commit log corruption was reported. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Re-Exception-when-starting-tp6383464p6387101.html Sent from the cassandra-u...@incubator.apache.org mailing lis

Re: Exception when starting

Brandon Williams wrote: > > There was a bug, it is fixed. It's just a cache, chill. > There is no time to chill when fighting it in production :) It's good to know it's fixed. Another question, when this happens are we able to restore data from replica nodes? -- View this message in context:

Re: Cassandra Vs. Oracle Coherence

Coherence is similar to memcachd (free). It's in memory cache layer on top of the DB. You as a user need to keep that cache in sync with the DB. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Cassandra-Vs-Oracle-Coherence-tp6375561p6386847.html S

Re: How to reduce the Read Latency.

What's your avg column size and row size? Your read latency in most case will directly be related to how much you are trying to read. In my experience you will see high read latency if you have big column size. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2

Re: Exception when starting

Whenever I hear someone say data is corrupted I panic :) I have seen few people have reported that but have not seen the real reason for it. Is it a manual error, config error, bug etc. It will be good to identify why these things happen so that it can be fixed before it happens in PROD :( -- Vie

Re: Inconsistent results using secondary indexes between two DC

I am wondering if running nodetool repair will help in anyway -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Inconsistent-results-using-secondary-indexes-between-two-DC-tp632p6382819.html Sent from the cassandra-u...@incubator.apache.org mail

Re: Commitlog Disk Full

Those messages are "ok" to ignore. It's basically deleting the files that are already flused as SSTables. Which version are you running? Have you tried restarting the node? Pick one node and send "ls -ltr" output also the complete log files since your last restart from the same node. I looked at

Re: Commitlog Disk Full

Do you see anything in log files? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Commitlog-Disk-Full-tp6356797p6374234.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.

Re: Commitlog Disk Full

You can try to update column family using cassandra-cli. Try to set memtable_throughput to 32 first. [default@unknown] help update column family; update column family Bar; update column family Bar with =; update column family Bar with = and =...; Update a column family with the specified values f

Re: Commitlog Disk Full

5G in one hour is actually very low. Something else is wrong. Peter pointed to something related to memtable size could be causing this problem, can you turn down memtable_throughput and see if that helps. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabb

Re: Commitlog Disk Full

Is there a way to look at the actual size of memtable? Would that help? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Commitlog-Disk-Full-tp6356797p6360001.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.co

Re: low performance inserting

Did you do a bulk upload with mysql from the same machine or separate insert/commit for each row? And did you run inserts from the same machine as the mysqld server? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/low-performance-inserting-tp63268

Re: Strange corrupt sstable

What do you mean by Bad memory? Is it less heap size, OOM issues or something else? What happens in such scenario, is there a data loss? Sorry for many questions just trying to understand since data is critical afterall :) -- View this message in context: http://cassandra-user-incubator-apache-o

Re: Strange corrupt sstable

Can someone please help understand the reason for corrupt SSTables? I am just worried what the worst case. Do we lose data in these cases? How to protect from data loss if that's the case. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Strange-co

Re: AW: AW: Two versions of schema

What would be the procedure in this case? Run drain on the node that is disagreeing? But is it enough to run just drain or you suggest drain + rm system files? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Two-versions-of-schema-tp6277365p628786

Re: AW: Two versions of schema

In my case all hosts were reachable and I ran nodetool ring before running the schema update. I don't think it was because of node being down. I tihnk for some reason it just took over 10 secs because I was reducing key_cache from 1M to 1000. I think it might be taking long to trim the keys hence 1

Re: Two versions of schema

I don't think I got correct answer to my original post. Can someone please help? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Two-versions-of-schema-tp6277365p6280070.html Sent from the cassandra-u...@incubator.apache.org mailing list archive a

Re: Key cache hit rate

You mean read it like .00038880248833592535E? I didn't quite follow why? If it is 3.8880248833592535E then does it mean I got only 3% hit or .0003? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Key-cache-hit-rate-tp6277236p6278397.html Sent from

Two versions of schema

Is there a problem? [default@StressKeyspace] update column family StressStandard with keys_cached=100; 854ee0a0-6792-11e0-81f9-93d987913479 Waiting for schema agreement... The schema has not settled in 10 seconds; further migrations are ill-advised until it does. Versions are 854ee0a0-6792-11e0-8

Key cache hit rate

How to intepret "Key cache hit rate"? What does this no mean? Keyspace: StressKeyspace Read Count: 87579 Read Latency: 11.792417360326105 ms. Write Count: 179749 Write Latency: 0.009272318622078566 ms. Pending Tasks: 0 Column Family: Stres

All nodes down even though ring shows up

I ran stress test to read 50K rows and since then I am getting below error even though ring show all nodes are up: ERROR 12:40:29,999 Exception: me.prettyprint.hector.api.exceptions.HectorException: All host pools marked down. Retry burden pushed out to client. at me.prettyprint.cassandra.

Re: flush_largest_memtables_at messages in 7.4

Actually when I run 2 stress clients in parallel I see Read Latency stay the same. I wonder if cassandra is reporting accurate nos. I understand your analogy but for some reason I don't see that happening with the results I am seeing with multiple stress clients running. So I am just confused wher

Re: flush_largest_memtables_at messages in 7.4

I still don't understand. You would expect read latency to increase drastically when it's fully saturated and lot of READ drop messages also, correct? I don't see that in cfstats or system.log which I don't really understand why. -- View this message in context: http://cassandra-user-incubator-ap

Re: flush_largest_memtables_at messages in 7.4

One correction qu size in iostat ranges between 6-120. But still this doesn't explain why read latency is low in cfstats. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/flush-largest-memtables-at-messages-in-7-4-tp6266221p6269875.html Sent from t

Re: flush_largest_memtables_at messages in 7.4

Peter Schuller wrote: > > Saturated. > But read latency is still something like 30ms which I would think would be much higher if it's saturated. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/flush-largest-memtables-at-messages-in-7-4-tp62662

Re: flush_largest_memtables_at messages in 7.4

Does it really matter how long cassandra has been running? I thought it will keep keys of 1M at least. Regarding your previous question about queue size in iostat I see it ranging from 114-300. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/fl

Re: flush_largest_memtables_at messages in 7.4

One thing I am noticing is that cache hit rate is very low even though my cache key size is 1M and I have less than 1M rows. Not sure why so many cache miss? Keyspace: StressKeyspace Read Count: 162506 Read Latency: 45.22479006928975 ms. Write Count: 247180 Write La

Re: flush_largest_memtables_at messages in 7.4

Yes -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/flush-largest-memtables-at-messages-in-7-4-tp6266221p6266726.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.

Re: Lot of pending tasks for writes

It does appear that I am IO bound. Disks show about 90% util. What are my options then? Is cassandra not suitable for columns of this size? I am running stress code from hector which doesn't sound like give ability to do operations per sec. I am insert 1M rows and then reading. Have not been able

Re: flush_largest_memtables_at messages in 7.4

64 bit 12 core 96 GB RAM -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/flush-largest-memtables-at-messages-in-7-4-tp6266221p6266400.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.

flush_largest_memtables_at messages in 7.4

I am using cassandra 7.4 and getting these messages. Heap is 0.7802529021498031 full. You may need to reduce memtable and/or cache sizes Cassandra will now flush up to the two largest memtables to free up memory. Adjust flush_largest_memtables_at threshold in cassandra.yaml if you don't want Cassa

Re: Lot of pending tasks for writes

Can someone please help? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Lot-of-pending-tasks-for-writes-tp6263462p6266213.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.

Re: Timeout during stress test

Here is what cfhistograms look like. Don't really understand what this means, will try to read. I also %util in iostat continuously 90%. Not sure if this is caused by extra reads by cassandra. It seems unusual. [root@dsdb4 ~]# nodetool -h `hostname` cfhistograms StressKeyspace StressStandard Stres

Re: Timeout during stress test

aaron morton wrote: > > You'll need to provide more information, from the TP stats the read stage > could not keep up. If the node is not CPU bound then it is probably IO > bound. > > > What sort of read? > How many columns was it asking for ? > How many columns do the rows have ? > Was the t

Re: Timeout during stress test

But I don't understand the reason for oveload. It was doing simple read of 12 threads and reasing 5 rows. Avg CPU only 20%, No GC issues that I see. I would expect cassandra to be able to process more with 6 nodes, 12 core, 96 GB RAM and 4 GB heap. -- View this message in context: http://cass

Lot of pending tasks for writes

I am running stress test and on one of the nodes I see: [root@dsdb5 ~]# nodetool -h `hostname` tpstats Pool NameActive Pending Completed ReadStage 0 0 2495 RequestResponseStage 0 0 242202 MutationStag

Re: Timeout during stress test

It looks like hector did retry on all the nodes and failed. Does this then mean cassandra is down for clients in this scenario? That would be bad. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Timeout-during-stress-test-tp6262430p6263270.html Se

Re: Timeout during stress test

I see this occurring often when all cassandra nodes all of a sudden show CPU spike. All reads fail for about 2 mts. GC.log and system.log doesn't reveal much. Only think I notice is that when I restart nodes there are tons of files that gets deleted. cfstats from one of the nodes looks like this:

Timeout during stress test

I am running stress test using hector. In the client logs I see: me.prettyprint.hector.api.exceptions.HTimedOutException: TimedOutException() at me.prettyprint.cassandra.service.ExceptionsTranslatorImpl.translate(ExceptionsTranslatorImpl.java:32) at me.prettyprint.cassandra.service

Re: Columns values(integer) need frequent updates/ increments

What's the difference between a row index and sstable index? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Columns-values-integer-need-frequent-updates-increments-tp6251464p6259882.html Sent from the cassandra-u...@incubator.apache.org mailing l

Re: Columns values(integer) need frequent updates/ increments

That I understand but my basic quesiton was how does it know that there are multiple updates that have occurred on the same column? and how does it efficiently knows which sstable have these updates? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com

Re: Heads up: restarting a node with autobootstrap=true after nodetool move will re-bootstrap the node in 0.7.0-0.7.4

Thanks for the info! Does this also happens if initial_token is set? Also, I am unable to understand the last line in that JIRA > A potential complication was that seed nodes were moved without using the > correct procedure of de-seeding them first. This was clearly wrong > What is de-seedin

Re: Columns values(integer) need frequent updates/ increments

If there are multiple updates to same columns and scattered accross multiple sstables then how does cassandra know which sstable has the most recent value. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Columns-values-integer-need-frequent-update

Re: What need to be monitored while running stress test

What is a storage proxy latency? By query latency you mean the one in cfstats and cfhistorgrams? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/What-need-to-be-monitored-while-running-stress-test-tp6255765p6257932.html Sent from the cassandra-u.

What need to be monitored while running stress test

What are the key things to monitor while running a stress test? There is tons of details in nodetoll tpstats/netstats/cfstats. What in particular should I be looking at? Also, I've been looking at iostat and await really goes high but cfstats shows low latency in microsecs. Is latency in cfstats c

CF config for Stress Test

I am starting a stress test using hector on 6 node machine 4GB heap and 12 core. In hectore readme this is what I got by default: create keyspace StressKeyspace with replication_factor = 3 and placement_strategy = 'org.apache.cassandra.locator.SimpleStrategy'; use StressKeyspace; drop col

auto_bootstrap

in yaml: # Set to true to make new [non-seed] nodes automatically migrate data # to themselves from the pre-existing nodes in the cluster. Why only non-seed nodes? What if seed nodes need to bootstrap? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble

Re: LB scenario

I think best is to have global load balancer in front of web servers/app servers. And leave app servers to handle requests at local quoram. If data center goes down then load balancer will simply hand out only one DCs ips. -- View this message in context: http://cassandra-user-incubator-apache-or

Re: 0.7.4 - Cassandra Nodes Do Not Start

I see this error in the logs posted. Is this normal? java.io.IOError: java.io.EOFException at org.apache.cassandra.net.IncomingTcpConnection.run(IncomingTcpConnection.java:73) Caused by: java.io.EOFException at java.io.DataInputStream.readInt(DataInputStream.java:375) at or

Re: Understanding cfhistogram output

I can't find it on wiki. Do you have a link where it can give detail help? Also, is the latency in micro sec. or millisec? How about latency in cfstats? Is it micro or mill? It says ms which is gen. millisec. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2

Re: Endless minor compactions after heavy inserts

I have seen on wiki also that in order to get better performance by setting compaction thread priority http://wiki.apache.org/cassandra/PerformanceTuning http://wiki.apache.org/cassandra/PerformanceTuning My question is if it improves performance then why is this not set by default? What's the do

Re: Endless minor compactions after heavy inserts

Is there a way to monitor the compactions using nodetools? I don't see it in tpstats. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Endless-minor-compactions-after-heavy-inserts-tp6229633p6231672.html Sent from the cassandra-u...@incubator.apach

RE: Ditching Cassandra

Where can I read more about CQL? I am assuming it's similar to SQL and drivers like JDBC can be written on top of it. Is that right? -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Ditching-Cassandra-tp6221436p6231654.html Sent from the cassandra-

Re: nodetool cfstathistogram error

It looks like if I use system schema it fails. Is it because of LocalPartitioner? I ran with other keyspace and got following output. Offset SSTables Write Latency Read Latency Row Size Column Count 1 0 0 0 0 0 2 0 0 0 0 0 179 0 0 0 320 320 Can someone please help me understand the output in fi

nodetool cfstathistogram error

Cassandra 7.4: nodetool -h `hostname` cfhistograms system schema Exception in thread "main" java.lang.reflect.UndeclaredThrowableException at $Proxy5.getRecentReadLatencyHistogramMicros(Unknown Source) at org.apache.cassandra.tools.NodeCmd.printCfHistograms(NodeCmd.java:452)

Re: How to determine if repair need to be run

If I am not wrong node repair need to be run on all the nodes in staggerred manner. It is required to take care of tombstones. Please correct me team if I am wrong :) See Distributed Deletes: http://wiki.apache.org/cassandra/Operations -- View this message in context: http://cassandra-user-in

Re: Ditching Cassandra

I am also interested in knowing when 8 will be released. Also, is there someplace where we can read about features that will be relased in 8? Looks like some major changes are going to come out. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Ditc

Re: How to determine if repair need to be run

I think what I feel is that there is a need to know if repair is required flag in order for team to manage the cluster. Atleast at minimum, Is there a flag somewhere that tells if repair was run within GCGracePeriod? -- View this message in context: http://cassandra-user-incubator-apache-org.306

Re: How to determine if repair need to be run

So from what I am understanding is that there is no need to monitor this and no need to remember running repair? If that's the case then manual repair wouldn't be needed ever, correct? But if Manual repair is needed then shouldn't there be ability to monitor? Having dealt with production problems

Re: How to determine if repair need to be run

Looks like you didn't get to see my updated post :) This is the scenario I was referring to: Say Node A, B, C. Now A is inconsistent and needs repair. Now after a day Node B goes down and comes up. Now both nodes are inconsistent. Even with Quorum this will fail read and write by returning inconsi

Re: How to determine if repair need to be run

I think my problem is that I don't want to remember to run read repair. I want to know from cassandra that I "need" to run repair "now". This seems like a important functionality that need to be there. I don't really want to find out hard way that I forgot to run "repair" :) Say Node A, B, C. Now

Re: How to determine if repair need to be run

Thanks! I was keeping the discussion simple. But you make my case stronger that we need such monitoring since it looks like it should always be run but we want to run it as soon as it is required. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Ho

Re: How to determine if repair need to be run

Yes but that doesn't really provide the monitoring that will really be helpful. If I don't realize it until 2 days then we potentially could be returning inconsistent results or not have data sync for 2 days until repair is run. It will be best to be able to monitor these things so that it can be r

How to determine if repair need to be run

Is there a way to monitor and tell if one of the node require repair? For eg: Node was down and came back up but in the meantime HH were dropped. Now unless we are really careful in all the scenarios we wouldn't have any problems :) but in general when things are going awry you might forget about r

Re: Central monitoring of Cassandra cluster

Thanks everyone this gives me a good head start. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Central-monitoring-of-Cassandra-cluster-tp6205275p6208331.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.

Central monitoring of Cassandra cluster

Can someone share if they have centralized monitoring for all cassandra servers. With many nodes it becomes difficult to monitor them individually unless we can look at data in one place. I am looking at solutions where this can be done. Looking at Cacti currently but not sure how to integrate it w

Re: Active / Active Data Center and RF

I think what I am trying to ask is this: what happens if it's RF=3 with network toplogy (RackInferringSnitch) and 2 copies are stored in Site A and 1 copy in Site B data center. Now client for some reason is directed to Site B data center and does a write/update on existing column, now would Site

Re: Active / Active Data Center and RF

CL is just a way to satisfy consistency but you still want majority of your reads (preferrably) occurring in the same DC. I don't think that answers my question at all. I understand the CL but I think I have more basic and important question about active/active data center and the replicas in that

Active / Active Data Center and RF

When in active/active data center how to decide right replication factor? Client may connect and request for the information from either data center so if locally it's RF=3 then in multiple data center should it be RF=6 in active/active? Or what happens if it's RF=3 with network toplogy and 2 copi

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