Hi,
In our hdfs, there are lots of(10 millions) ~4 KB files. That is why we have to increase the ipc.maximum.data.length to hold that much block report. And yes this is a problem we are facing in our scenario. We have opted for HAR archives to bundle 100 k files in one HAR. Thus reducing the total block count as a work around to the problem. Regards Om Prakash From: Gurmukh Singh [mailto:[email protected]] Sent: 25 August 2017 17:22 To: omprakash <[email protected]>; [email protected] Cc: 'surendra lilhore' <[email protected]>; [email protected] Subject: Re: Namenode not able to come out of SAFEMODE Hi Om, Although you solved this issue by bumping up the ipc max length which is by default set to 64MB. $ hdfs getconf -confkey ipc.maximum.data.length 67108864 So, it means the disk you are using is having more then 1 million blocks. Are you using HDFS block size to be very small ? If you are keeping the HDFS block size to 64MB, you can a disk of size 64TB before you start seeing this error. Looks like you are doing something wrong. Having a large value of ipc max will increase the serialization and de-serialization time for protobuf. On 20/7/17 7:01 pm, omprakash wrote: Hi, Thanks for the quick reply. That was exactly the problem. The datanodes were throwing error of "maximum IPC message length size not enough" but we were focusing on NameNodes only. I changed the "ipc.maximum.data.length" property in core-site.xml file(I found this solution of above error after searcing over internet) and restarted the namenode and datanode. After an hour all the blocks get loaded successfully. Thanks for the help again. Regards Om From: surendra lilhore [mailto:[email protected]] Sent: 20 July 2017 12:12 To: omprakash <mailto:[email protected]> <[email protected]>; [email protected] <mailto:[email protected]> Subject: RE: Namenode not able to come out of SAFEMODE Hi Omprakash, The reported blocks 0 needs additional 6132675 blocks to reach the threshold 0.9990 of total blocks 6138814. The number of live datanodes 0 has reached the minimum number 0. -----------> By seeing this message looks like NameNode loaded the block info into memory but the reported blocks from the Datanodes are "0". Maybe datanodes are not running, if it is running then please check why it's not registered with namenode. You can check the datanode log for more details. Regards, Surendra _____ From: omprakash [[email protected] <mailto:[email protected]> ] Sent: Thursday, July 20, 2017 12:12 AM To: <mailto:[email protected]> [email protected] Subject: Namenode not able to come out of SAFEMODE Hi all, I have a setup of 3 node Hadoop cluster(Hadoop-2.8.0). I have deployed 2 namenodes that are configured in HA mode using QJM. 2 datanodes are configured on the same machine where namenode are installed. 3rd node is used for quorum purpose only. Setup Node1 -> nn1, dn1, jn1, zkfc1, zkServer1 Node2 -> nn2, dn2, jn2, zkfc2, zkServer2 Node3 -> jn3, zkServer3 I stopped the cluster for some reason(power recycled the servers) and since them I am not able to start the cluster successfully. After examining the logs I found that the namenodes are in safe mode and none of them are able to load the block in memory. Below is the status of namenode from namenode UI. Safe mode is ON. The reported blocks 0 needs additional 6132675 blocks to reach the threshold 0.9990 of total blocks 6138814. The number of live datanodes 0 has reached the minimum number 0. Safe mode will be turned off automatically once the thresholds have been reached. 61,56,984 files and directories, 61,38,814 blocks = 1,22,95,798 total filesystem object(s). Heap Memory used 5.6 GB of 7.12 GB Heap Memory. Max Heap Memory is 13.33 GB. Non Heap Memory used 45.19 MB of 49.75 MB Commited Non Heap Memory. Max Non Heap Memory is 130 MB. I have tried increasing the HADOOP_HEAPSIZE, increasing the heap size in HADOOP_NAMENODE_OPTS but no success. Need help. Regards Omprakash Paliwal HPC-Medical and Bioinformatics Applications Group Centre for Development of Advanced Computing (C-DAC) Pune University campus, PUNE-411007 Maharashtra, India email:[email protected] <mailto:[email protected]> Contact : +91-20-25704231 ---------------------------------------------------------------------------- --------------------------------------------------- [ C-DAC is on Social-Media too. Kindly follow us at: Facebook: <https://www.facebook.com/CDACINDIA> https://www.facebook.com/CDACINDIA & Twitter: @cdacindia ] This e-mail is for the sole use of the intended recipient(s) and may contain confidential and privileged information. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies and the original message. Any unauthorized review, use, disclosure, dissemination, forwarding, printing or copying of this email is strictly prohibited and appropriate legal action will be taken. ---------------------------------------------------------------------------- --------------------------------------------------- ---------------------------------------------------------------------------- --------------------------------------------------- [ C-DAC is on Social-Media too. Kindly follow us at: Facebook: https://www.facebook.com/CDACINDIA & Twitter: @cdacindia ] This e-mail is for the sole use of the intended recipient(s) and may contain confidential and privileged information. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies and the original message. Any unauthorized review, use, disclosure, dissemination, forwarding, printing or copying of this email is strictly prohibited and appropriate legal action will be taken. ---------------------------------------------------------------------------- --------------------------------------------------- ------------------------------------------------------------------------------------------------------------------------------- [ C-DAC is on Social-Media too. Kindly follow us at: Facebook: https://www.facebook.com/CDACINDIA & Twitter: @cdacindia ] This e-mail is for the sole use of the intended recipient(s) and may contain confidential and privileged information. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies and the original message. Any unauthorized review, use, disclosure, dissemination, forwarding, printing or copying of this email is strictly prohibited and appropriate legal action will be taken. -------------------------------------------------------------------------------------------------------------------------------
