Re: Load spikes when new email arrives

2013-01-25 Thread francis picabia
On Fri, Jan 25, 2013 at 10:26 AM, Blake Hudson wrote: > > francis picabia wrote the following on 1/25/2013 7:55 AM: > > > On Thu, Jan 24, 2013 at 12:22 PM, Blake Hudson wrote: > >> >> >> There are a couple suggestions I'd like to put forth. First, improper >> partition alignment is generally ma

Re: Load spikes when new email arrives

2013-01-25 Thread Blake Hudson
francis picabia wrote the following on 1/25/2013 7:55 AM: On Thu, Jan 24, 2013 at 12:22 PM, Blake Hudson > wrote: There are a couple suggestions I'd like to put forth. First, improper partition alignment is generally masked by the controller cache. I stron

Re: Load spikes when new email arrives

2013-01-25 Thread francis picabia
On Thu, Jan 24, 2013 at 12:22 PM, Blake Hudson wrote: > > > There are a couple suggestions I'd like to put forth. First, improper > partition alignment is generally masked by the controller cache. I > strongly encourage you to check that your RAID array is making use of > this cache by enabling t

Re: Load spikes when new email arrives

2013-01-25 Thread Jean Raby
On 13-01-23 11:16 AM, francis picabia wrote: > > Here are more stats. Do these look average for performance? > It is difficult to understand why the system was working with few > load spikes before. > > A mailman mailing list sends 10kbyte message to 4000 > users having accounts on this cyrus syst

Re: Load spikes when new email arrives

2013-01-24 Thread Andrew Morgan
On Thu, 24 Jan 2013, francis picabia wrote: > In another email discussion on the Redhat mailing list, I've confirmed we > have > an issue with partition alignment. This is getting to be quite the mess > out there. I saw one posting where it is speculated there are thousands of > poorly set up di

Re: Load spikes when new email arrives

2013-01-24 Thread francis picabia
On Thu, Jan 24, 2013 at 2:06 PM, Wesley Craig wrote: > You might find this helpful: > > http://lwn.net/Articles/328363/ > > regarding fsync (lmtpd) latency on Linux. Lowering the lmtpd process > limit ought to fix your load problem, but you should be aware how cyrus > master implements t

Re: Load spikes when new email arrives

2013-01-24 Thread Simon Matter
> >> In another email discussion on the Redhat mailing list, I've confirmed >> we have >> an issue with partition alignment. This is getting to be quite the mess >> out there. I saw one posting where it is speculated there are >> thousands of >> poorly set up disk partitions for their RAID stripe

Re: Load spikes when new email arrives

2013-01-24 Thread Blake Hudson
> In another email discussion on the Redhat mailing list, I've confirmed > we have > an issue with partition alignment. This is getting to be quite the mess > out there. I saw one posting where it is speculated there are > thousands of > poorly set up disk partitions for their RAID stripe size

Re: Load spikes when new email arrives

2013-01-24 Thread francis picabia
On Wed, Jan 23, 2013 at 5:25 PM, Andrew Morgan wrote: > On Wed, 23 Jan 2013, francis picabia wrote: > > Thanks for the response. I have been checking my iostat whenever there is >> a number of messages in the active queue. >> >> Here is a sample snapshot from a script I run (ignoring the first

Re: Load spikes when new email arrives

2013-01-23 Thread Andrew Morgan
On Wed, 23 Jan 2013, francis picabia wrote: > Thanks for the response. I have been checking my iostat whenever there is > a number of messages in the active queue. > > Here is a sample snapshot from a script I run (ignoring the first > iostat output of averages): > > Active in queue: 193 > 12:47:

Re: Load spikes when new email arrives

2013-01-23 Thread Vincent Fox
On 01/23/2013 08:16 AM, francis picabia wrote: > > I've also backed out the change (yesterday) to > /sys/block/sda/queue/nr_requests > I think it was pushing the load higher and there is no advantage > in my hardware (SAS with Perc 5/i Raid 5 over 4 disk) > to run with a low value for nr_requests.

Re: Load spikes when new email arrives

2013-01-23 Thread francis picabia
On Wed, Jan 23, 2013 at 1:55 PM, Andrew Morgan wrote: > On Wed, 23 Jan 2013, francis picabia wrote: > > Here are more stats. Do these look average for performance? >> It is difficult to understand why the system was working with few >> load spikes before. >> >> A mailman mailing list sends 10kb

Re: Load spikes when new email arrives

2013-01-23 Thread Andrew Morgan
On Wed, 23 Jan 2013, francis picabia wrote: > Here are more stats. Do these look average for performance? > It is difficult to understand why the system was working with few > load spikes before. > > A mailman mailing list sends 10kbyte message to 4000 > users having accounts on this cyrus system

Re: Load spikes when new email arrives

2013-01-23 Thread francis picabia
Here are more stats. Do these look average for performance? It is difficult to understand why the system was working with few load spikes before. A mailman mailing list sends 10kbyte message to 4000 users having accounts on this cyrus system. If I grep "Delivered" in the maillog by the minute I