[Gluster-users] gluster fails under heavy array job load load

harry mangalam harry.mangalam at uci.edu
Fri Dec 13 01:03:12 UTC 2013

Hi All,
(Gluster Volume Details at bottom)

I've posted some of this previously, but even after various upgrades, 
attempted fixes, etc, it remains a problem.

Short version:  Our gluster fs (~340TB) provides scratch space for a ~5000core 
academic compute cluster.  
Much of our load is streaming IO, doing a lot of genomics work, and that is 
the load under which we saw this latest failure.
Under heavy batch load, especially array jobs, where there might be several 
64core nodes doing I/O on the 4servers/8bricks, we often get job failures that 
have the following profile:

Client POV:
Here is a sampling of the client logs (/var/log/glusterfs/gl.log) for all 
compute nodes that indicated interaction with the user's files

Here are some client Info logs that seem fairly serious:

The errors that referenced this user were gathered from all the nodes that 
were running his code (in compute*) and agglomerated with:

cut -f2,3 -d']' compute* |cut -f1 -dP | sort | uniq -c | sort -gr 

and placed here to show the profile of errors that his run generated.

so 71 of them were:
  W [client-rpc-fops.c:2624:client3_3_lookup_cbk] 0-gl-client-7: remote 
operation failed: Transport endpoint is not connected. 

We've seen this before and previously discounted it bc it seems to have been 
related to the problem of spurious NFS-related bugs, but now I'm wondering 
whether it's a real problem. 
Also the 'remote operation failed: Stale file handle. ' warnings.

There were no Errors logged per se, tho some of the W's looked fairly nasty, 
like the 'dht_layout_dir_mismatch'

>From the server side, however, during the same period, there were:
0 Warnings about this user's files
0 Errors 
458 Info lines
of which only 1 line was not a 'cleanup' line like this:
---[2013-12-12 21:22:01.064289] I [server-helpers.c:460:do_fd_cleanup] 
0-gl-server: fd cleanup on /path/to/file
it was:
---[2013-12-12 21:00:35.209015] I [server-rpc-
fops.c:898:_gf_server_log_setxattr_failure] 0-gl-server: 113697332: SETXATTR 
/bio/tdlong/RNAseqIII/ckpt.1084030 (c9488341-c063-4175-8492-75e2e282f690) ==> 

We're losing about 10% of these kinds of array jobs bc of this, which is just 
not supportable.

Gluster details

servers and clients running gluster 3.4.0-8.el6 over QDR IB, IPoIB, thru 2 
Mellanox, 1 Voltaire switches, Mellanox cards, CentOS 6.4

$ gluster volume info
Volume Name: gl
Type: Distribute
Volume ID: 21f480f7-fc5a-4fd8-a084-3964634a9332
Status: Started
Number of Bricks: 8
Transport-type: tcp,rdma
Brick1: bs2:/raid1
Brick2: bs2:/raid2
Brick3: bs3:/raid1
Brick4: bs3:/raid2
Brick5: bs4:/raid1
Brick6: bs4:/raid2
Brick7: bs1:/raid1
Brick8: bs1:/raid2
Options Reconfigured:
performance.write-behind-window-size: 1024MB
performance.flush-behind: on
performance.cache-size: 268435456
nfs.disable: on
performance.io-cache: on
performance.quick-read: on
performance.io-thread-count: 64
auth.allow: 10.2.*.*,10.1.*.*

'gluster volume status gl detail': 

Harry Mangalam - Research Computing, OIT, Rm 225 MSTB, UC Irvine
[m/c 2225] / 92697 Google Voice Multiplexer: (949) 478-4487
415 South Circle View Dr, Irvine, CA, 92697 [shipping]
MSTB Lat/Long: (33.642025,-117.844414) (paste into Google Maps)
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