[Ocfs2-users] ENOSPC

[Sunil Mushran]

Quite a bit of work is ongoing on this front. I'll list all that work
in another email.

Meanwhile make a bz with the stat_sysdir output. We'll need that
to determine the best way forward.

David Johle wrote:
> So in light of prior issues with lock contention and such due to 
> writing apache logs to shared files I have started storing them 
> locally on each node.  I made a script to combine them nightly before 
> the statistics generator kicks off for the previous day's traffic analysis.
>
> This script, using logresolvemerge.pl, is actually writing the output 
> back to the shard volume for easy reference later.  I figure I would 
> not have issues with this as it's a large amount of sequential writes 
> from a single node at off-peak time.  However, It's been getting hung 
> with high CPU from the merger.
>
> I'm pretty sure I'm running into the famous "free space 
> fragmentation" problem, but wanted to confirm that this was the case 
> or see if there was additional troubleshooting I can do.
>
> Here's the disk, plenty of overall free space:
>
> Filesystem           1K-blocks      Used Available Use% Mounted on
> /dev/mapper/mpath1   209725440  85311460 124413980  41% /san/live-websites
>
>
> While my merging was going 100% of a CPU core, but the merged file 
> was not growing in size and not much I/O actually happening to the 
> shared volume, I did an strace to see what it was doing and got this:
>
> # strace -p 16844
> Process 16844 attached - interrupt to quit
> read(3, "1\" 200 936 \"http://www.industria"..., 4096) = 4096
> write(1, ".NET CLR 1.1.4322; .NET CLR 2.0."..., 4096) = -1 ENOSPC (No 
> space left on device)
> read(4, "oration&locationName=South+Jerse"..., 4096) = 4096
> write(1, "ivers=8&ngPipelines=600&kvtl230="..., 4096) = -1 ENOSPC (No 
> space left on device)
> read(4, "1\" 200 936 \"http://www.industria"..., 4096) = 4096
> write(1, "gan+Boulevard&locationCSZ=Salem%"..., 4096) = -1 ENOSPC (No 
> space left on device)
> read(3, "HTTP/1.0\" 200 4096 \"-\" \"WinampMP"..., 4096) = 4096
> write(1, "elta=.375&zoomlevel=6&label=Sout"..., 4096) = -1 ENOSPC (No 
> space left on device)
> read(4, "HTTP/1.0\" 200 4096 \"-\" \"WinampMP"..., 4096) = 4096
> write(1, "ident/4.0; .NET CLR 1.1.4322; .N"..., 4096) = -1 ENOSPC (No 
> space left on device)
> read(3, "0 36516 \"-\" \"Mozilla/5.0 (compat"..., 4096) = 4096
>
>
> Now I'm really worried about the cluster stability from other routine 
> writes that might fail soon.  I know the typical workaround is to 
> reduce the node slots, but I don't have any excess slots to 
> spare.  Are there any other tricks to improve/reduce freespace fragmentation?
>
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