July 2014 - HPDD-discuss

by John Bauer

I have been trying to understand a behavior I am observing in an IOR benchmark on Lustre. I have pared it down to a simple example. The IOR benchmark is running in MPI mode. There are 2 ranks, each running on its own node. Each rank does the following: Note : Test was run on the "swan" cluster at Cray Inc., using /lus/scratch write a file. ( 10GB ) fsync the file close the file MPI_barrier open the file that was written by the other rank. read the file that was written by the other rank. close the file that was written by the other rank. The writing of each file goes as expected. The fsync takes very little time ( about .05 seconds). The first reads of the file( written by the other rank ) start out *very *slowly. While theses first reads are proceeding slowly, the kernel's cached memory ( the Cached: line in /proc/meminfo) decreases from the size of the file just written to nearly zero. Once the cached memory has reached nearly zero, the file reading proceeds as expected. I have attached a jpg of the instrumentation of the processes that illustrates this behavior. My questions are: Why does the reading of the file, written by the other rank, wait until the cached data drains to nearly zero before proceeding normally. Shouldn't the fsync ensure that the file's data is written to the backing storage so this draining of the cached memory should be simply releasing pages with no further I/O? For this case the "dead" time is only about 4 seconds, but this "dead" time scales directly with the size of the files. John -- John Bauer I/O Doctors LLC 507-766-0378 bauerj(a)iodoctors.com

5 years, 10 months

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quotas on 2.4.3

by Matt Bettinger

Hello, We have a fresh 2.4.3 lustre upgrade that is not yet put into production running on rhel 6.4. We would like to take a look at quotas but looks like there is some major performance problems with 1.8.9 clients. Here is how I enabled quotas [root@lfs-mds-0-0 ~]# lctl conf_param lustre2.quota.mdt=ug [root@lfs-mds-0-0 ~]# lctl conf_param lustre2.quota.ost=ug [root@lfs-mds-0-0 ~]# lctl get_param osd-*.*.quota_slave.info osd-ldiskfs.lustre2-MDT0000.quota_slave.info= target name: lustre2-MDT0000 pool ID: 0 type: md quota enabled: ug conn to master: setup space acct: ug user uptodate: glb[1],slv[1],reint[0] group uptodate: glb[1],slv[1],reint[0] The quotas seem to be working however the write performance from 1.8.9wc client to 2.4.3 with quotas on is horrific. Am I not setting quotas up correctly? I try to make a simple user quota on /lustre2/mattb/300MB_QUOTA directory [root@hous0036 mattb]# lfs setquota -u l0363734 -b 307200 -B 309200 -i 10000 -I 11000 /lustre2/mattb/300MB_QUOTA/ See quota change is in effect... [root@hous0036 mattb]# lfs quota -u l0363734 /lustre2/mattb/300MB_QUOTA/ Disk quotas for user l0363734 (uid 1378): Filesystem kbytes quota limit grace files quota limit grace /lustre2/mattb/300MB_QUOTA/ 310292* 307200 309200 - 4 10000 11000 - Try and write to quota directory as the user but get horrible write speed [l0363734@hous0036 300MB_QUOTA]$ dd if=/dev/zero of=301MB_FILE bs=1M count=301 301+0 records in 301+0 records out 315621376 bytes (316 MB) copied, 61.7426 seconds, 5.1 MB/s Try file number 2 and then quota take effect, so it seems. [l0363734@hous0036 300MB_QUOTA]$ dd if=/dev/zero of=301MB_FILE2 bs=1M count=301 dd: writing `301MB_FILE2': Disk quota exceeded dd: closing output file `301MB_FILE2': Input/output error If I disable quotas using [root@lfs-mds-0-0 ~]# lctl conf_param lustre2.quota.mdt=none [root@lfs-mds-0-0 ~]# lctl conf_param lustre2.quota.oss=none Then try and write the same file the speeds are more like we expect but then can't use quotas. [l0363734@hous0036 300MB_QUOTA]$ dd if=/dev/zero of=301MB_FILE2 bs=1M count=301 301+0 records in 301+0 records out 315621376 bytes (316 MB) copied, 0.965009 seconds, 327 MB/s [l0363734@hous0036 300MB_QUOTA]$ dd if=/dev/zero of=301MB_FILE2 bs=1M count=301 I have not tried this with a 2.4 client, yet since all of our nodes are 1.8.X until we rebuild our images. I was going by the manual on http://build.whamcloud.com/job/lustre-manual/lastSuccessfulBuild/artifact... but it looks like I am running into interoperability issue (which I thought I fixed by using 1.8.9-wc client) or just not configuring this correctly. Thanks! MB

6 years, 1 month

5
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New liblustreapi ?

by Simmons, James A.

Now that lustre 2.7 is coming up soon I like to open the discussion on one of the directions we could go. Recently several projects have sprung up that impact liblustreapi. During one of those discussion the idea of a new liblustreapi was brought up. A liblustreapi 2.0 you could say. So I like to get feel in the community about this. If people want this proposal I like to recommend that we gradually build this new library along side the original liblustreapi and link it when necessary to the lustre utilities. First I like the discussion of using the LGPL license with this new library. I look forward to the feed back.

6 years, 3 months

2
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Lustre 2.6.0 released

by Jones, Peter A

We are pleased to announce that the Lustre 2.6.0 Release has been declared GA and is available for download<https://downloads.hpdd.intel.com/public/lustre/latest-feature-release/> . You can also grab the source from git<http://git.whamcloud.com/fs/lustre-release.git/commit/73ea776053d99f74a9f...> This major release includes new features: MDT-OST Consistency Check and Repair (LFSCK Phase 2)- Allows the MDS to verify the consistency of a Lustre filesystem while it is mounted and in use. The latest enhancements are to check and repair the validity of OST objects of regular files and to identify and optionally remove or link into lost+found OST objects that are not referenced by any files on the MDS. This development is funded by OpenSFS (LU-1267<https://jira.hpdd.intel.com/browse/LU-1267>) Single Client Performance Improvements – Single thread per process IO performance has been improved. This work was discussed in details at LUG<http://cdn.opensfs.org/wp-content/uploads/2014/04/D1_S6_LustreClientIOPer...> (LU-3321<https://jira.hpdd.intel.com/browse/LU-3321>) Striped Directories -Enables a single directory to be striped across multiple MDTs to improve single directory performance and scalability. This is a technology preview of part of the DNE phase 2 work funded by OpenSFS that will be fully available in a future Lustre release (LU-3531<https://jira.hpdd.intel.com/browse/LU-3531>) Fuller details can be found in the change log<https://wiki.hpdd.intel.com/display/PUB/Changelog+2.6>, the scope statement<https://wiki.hpdd.intel.com/display/PUB/Lustre+2.6+Scope+Statement> <https://wiki.hpdd.intel.com/display/PUB/Lustre+2.6+Scope+Statement> and the test mat<https://wiki.hpdd.intel.com/display/PUB/Lustre+2.6>rix<https://wiki.hpdd.intel.com/display/PUB/Lustre+2.6> The following are known issues in the Lustre 2.6 Release: LU-5057<https://jira.hpdd.intel.com/browse/LU-5057> - A rare race condition can lead to an LASSERT when unmounting an OST. LU-5150 <https://jira.hpdd.intel.com/browse/LU-5150> - Empty access control lists (ACLs) will be stored for copied files when using a ZFS MDS. It does not affect ldiskfs MDSes. LU-4367 -<https://jira.hpdd.intel.com/browse/LU-4367> Metadata performance is affected for unlinking files in a single shared directory in a manner common with mdtest benchmark pattern. LU-5420<https://jira.hpdd.intel.com/browse/LU-5420> - DNE configurations with multiple MDTs sharing a single node with an MGS may hang during MDT mount or fail to mount an MDT after unclean shutdown. Work is in progress for these issues. NOTE: Users should note that usage of the e2fsprogs-based lfsck has been deprecated and replaced by "lctl lfsck_start”. Using older e2fsprogs-based lfsck may lead to filesystem corruption. Once available, it is also recommended to use e2fsprogs-1.42.11.wc2 (or newer). Please log any issues found in the issue tracking system<https://jira.hpdd.intel.com/> We would like to thank OpenSFS<http://www.opensfs.org/>, for their contributions towards the cost of the release and also to all Lustre community members who have contributed to the release with code and/or testing.

6 years, 7 months

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Problem mounting clients after update to 2.5.2

by Oliver Mangold

Hi, I updated a Lustre installation from Lustre 2.1.6 to 2.5.2. Now something seems to be wrong with the llogs. After doing writeconf on all targets I can mount a client *once*, but after unmounting the client again, all subsequent tries to mount clients result in errors like this: 2014-07-31T12:57:12.198389+02:00 l3mds1 <kern.err> kernel:LustreError: 68983:0:(obd_mount.c:1323:lustre_fill_super()) Unable to mount (-5) 2014-07-31T12:57:13.198412+02:00 l3mds1 <kern.err> kernel:LustreError: 15c-8: MGC10.3.6.21@o2ib: The configuration from log 'lustre3-client' failed (-5). This may be the result of communication errors between this node and the MGS, a bad configuration, or other errors. See the syslog for more information. 2014-07-31T12:57:13.198428+02:00 l3mds1 <kern.err> kernel:LustreError: 69606:0:(llite_lib.c:1046:ll_fill_super()) Unable to process log: -5 Any ideas how to fix this? -- Dr. Oliver Mangold System Analyst NEC Deutschland GmbH HPC Division Hessbrühlstraße 21b 70565 Stuttgart Germany Phone: +49 711 78055 13 Mail: oliver.mangold(a)emea.nec.com

6 years, 7 months

1
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Moving the MDT performing File-level backups

by Ramiro Alba

Hello everybody, I am currently using Lustre 1.8.5 at servers, with a SLES kernel (2.6.32.19-0.2.1-lustre.1.8.5). Before this year is over, I'll upgrade to the current Lustre Maintenance release (currently 2.4.X), but now I need to arrange a MDT moving, to other LUN in the MDS. I did a test on a MDT LVM snapshot, following the moving procedure described bellow, but I found some issues I would like to comment: 1) The backup using the tar command took very long time (20 hours), though the MDT is quite small (197 MB). So long? 2) The restored 'ldiskfs' file system is a bit smaller than the original one (about 20 MB using du -sm). Should I worry? 3) When backing up Extended attributes with the command 'getfattr' I get some errors of the type: getfattr: ./ROOT/<file path>: No such file or directory I could see that they are symbolic links using absolute paths. Can that be a problem? Finally, I got the bellow procedure from the 1.8.X Lustre manual. Any comment? ************************************************************** MDT MOVING PROCEDURE ************************************************************** ---------------------------------------------------------- - Backup procedure ---------------------------------------------------------- 1) Mount lustre as 'ldiskfs' type mount -t ldiskfs /dev/sdb /lustre/mds 2) Change to the file system mount point cd /lustre/mds 3) Backup all the file system data tar cSf /backup/mds.tar . 4) Backup Extended Attributes getfattr -R -d -m '.*' -P . > /backup/ea.bak 5) Umount the file system cd umount /lustre/mds ---------------------------------------------------------- - Restore procedure ---------------------------------------------------------- 1) Make a receiving lustre MDT mkfs.lustre --fsname=jffstg --param mdt.quota_type=ug \ --reformat --mdt --mgs /dev/sdc 2) Mount lustre as 'ldiskfs' type mount -t ldiskfs /dev/sdc /lustre/mds 3) Change to the file system mount point cd /lustre/mds 4) Restore the previous tar file tar xpSf /backup/mds.tar 5) Restore de file system Extended Attributes setfattr --restore=/backup/ea.bak 6) Remove the recovery logs rm OBJECTS/* CATALOGS -- Ramiro Alba Centre Tecnològic de Tranferència de Calor http://www.cttc.upc.edu Escola Tècnica Superior d'Enginyeries Industrial i Aeronàutica de Terrassa Colom 11, E-08222, Terrassa, Barcelona, Spain Tel: (+34) 93 739 8928 -- Aquest missatge ha estat analitzat per MailScanner a la cerca de virus i d'altres continguts perillosos, i es considera que est� net.

6 years, 7 months

2
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Lustre 2.6 on Ubuntu 14

by Patrice Hamelin

Hi, I am trying to compile a Lustre 2.6 client on ubuntu 14.04, kernel 3.13.0 and Mellanox OFED 2.2-1. I saw that developpers work hard to get it supported, what is the status of this? Is it feasible? I did not succeed yet. Thanks. -- Patrice Hamelin Specialiste sénior en systèmes d'exploitation | Senior OS specialist Environnement Canada | Environment Canada Dorval, QC Gouvernement du Canada | Government of Canada

6 years, 7 months

5
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slow nid removal?

by Michael Di Domenico

I'm running lustre 2.4.3 on rhel6. I have 16 infiniband ipoib nids setup on my lustre servers. the networking seems to work fine. however, when i remove the nids using 'lctl net unconfigure' it seems to take 20-22 seconds to remove each one. there are no errors showing and the command works just fine, i'm just curious why it's taking so long. there are no other modules loaded, commands i ran are as follows modprobe lnet lctl net configure lctl net up do some lctl pings lctl net down lctl net unconfigure lustre_rmmod the unconfigure step seems to take 20-22 secs per nid, everything else is quick any thoughts? thanks - michael

6 years, 7 months

1
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Clang plugin for identifying un-used code.

by Henwood, Richard

Hi All, To aid completion of valuable Removal of Dead Code (Implementation) work funded by OpenSFS [1], Intel HPDD developed a tool to help identify unused functions, structure members, macros, and variables. I'm pleased that this tool is now available for anyone to pursue code clean-up work with automated help. This tool uses the Clang front-end, augmented by a specially written plugin. A guide to getting stared is available here: https://wiki.hpdd.intel.com/pages/viewpage.action?pageId=18645101 The plugin code that provides the necessary augmentation to Clang is available here: http://git.whamcloud.com/tools/lustre-static-analysis.git The code is available under GPLv2. best regards, Richard 1. http://wiki.opensfs.org/Contract_SFS-DEV-003 -- Richard.Henwood(a)intel.com Intel High Performance Data Division

6 years, 7 months

2
2
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Re: [HPDD-discuss] [Lustre-devel] lustre-1.8.8: rdma_listen() backlog 0 breaks iWARP

by Dilger, Andreas

On 2014/07/23, 9:44 AM, "Steve Wise" <swise(a)opengridcomputing.com> wrote: >Hello, > >I'm trying to get lustre-1.8.8/RHEL6 running over Chelsio iWARP RNICs and >connection setup >is failing at the server due to kiblnd_startup() calling rdma_listen() >with a backlog of >0. This effectively rejects all incoming connection requests. I looked >at lustre-1.8.7, >and the backlog was 256 in that release. > >Q: Why was it changed to 0? Since I'm not familiar with the LNET code myself, I'd recommend to check the commit messages in Git to see if there is an explanation, or in the linked Jira/Bugzilla ticket. You may also want to see if this is fixed with the 1.8.9 release. Cheers, Andreas -- Andreas Dilger Lustre Software Architect Intel High Performance Data Division

6 years, 7 months

1
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HPDD-discuss July 2014