Re: [Condor-users] Site-wide want_remote_io=false possible?

[Todd Tannenbaum <tannenba@xxxxxxxxxxx>]

Carsten Aulbert wrote:
> Hi,
>
> brief questions around want_remote_io:
>
> (1) Is it possible to enable this site-wide, e.g. change the default
> setting to False. I guess it is but so far I have failed to find that,
> how can that be done?

Well, you can tell condor_submit to add this setting by default into 
each submit file.  If you are able to edit the condor_config file(s) of 
all machines where your users run condor_submit, the following entry 
should do the job:

   SUBMIT_EXPRS = WantRemoteIO=True

(the Manual has more details on SUBMIT_EXPRS)

> (2) On our system users have their home file system under NFS and then
> can also use a local directory which is also automountable via NFS. Does
> the user need to avoid writing to the local disk under all circumstances
> when want_remote_io is set to false?

No, they can write to local disk, but realize in standard universe if 
they write to local disk then Condor will not do any work to send the 
files back to the submit machine; so writing to local disk is fine for 
temporary files (who will clean them up?) but not such a good idea for 
output files.

> The reason why we want to disable that is that our submit machines are
> under very heavy load when large standard usinverse jobs are run and we
> suspect remote io playing a key role here.

Maybe your UID_DOMAIN and FILESYSTEM_DOMAIN settings are incorrect?

See the section on shared filesystem settings for Condor in the Manual 
at URL:
http://www.cs.wisc.edu/condor/manual/v7.0/3_3Configuration.html#sec:Shared-Filesystem-Config-File-Entries

Basically, in standard universe if the UID_DOMAIN and the 
FILESYSTEM_DOMAIN of between the submit and execute machine are both 
equal, then Condor should use the shared filesystem to access the file 
and not use remote I/O.  Does your submit machine and execute machine 
mount the same shared filesystems on the same mount points?  If yes, 
then I would make sure the shared filesystem settings are correct and 
then Condor should "do the right thing(tm)" and not require you to 
disable remote I/O all the time.

> Thanks in advance

Sure, hope the above is helpful,
Todd