Comment 4 for bug 1536620

On 21.01.16 14:42, Cosmin coroiu wrote:
> however the way we checked the limit is by xargs --show-limits which outputs:
> POSIX smallest allowable upper limit on argument length (all systems): 4096

That's the default for xargs if nothing else is set. However, there
should be a line above with a much higher value, like this:

$ xargs --show-limits
POSIX upper limit on argument length (this system): 2092804
POSIX smallest allowable upper limit on argument length (all systems): 4096

Also, this is for xargs only, not the system itself.

> and as such we concluded the limit is 4096, also the rsync command
> itself stops suddenly at 4096 characters when checking the command with
> something like ps aux | grep rsync

That might be just the output line that is cutoff; in your reported case
it seems to be even less than 2000 chars.

You can increase the output with something like "ps aux --cols=10000".

> The log looks something like this when failing with rsync:
> Jan 21 04:12:59 srv-hostname object-replicator: Killing long-running rsync:
>
>[... snip - long line ... ]
>
> We tried increasing the rsync_timeout to 4 hours, but that doesn't help,
> as the destination path is missing because of the characters limit, we
> think.

I don't think the character limit is the problem, but there might be
another issue if it takes so long to replicate one partition.

What is your partition power for the object ring? You are only using one
2TB volume per node, so only 7 disks for the whole cluster?