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[Platforms #FVR-912211]: Best linux file system for data on large raid5 array?

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  • Subject: [Platforms #FVR-912211]: Best linux file system for data on large raid5 array?
  • Date: Tue, 09 Oct 2007 02:35:42 -0600
Hi Pete,

I just wanted to let you know that we don't run any large (multiple TB) RAID5 
arrays under Linux.  We have all been following the discussions that were
kicked off by your note to ldm-users.  I must tell you that my experience
in building a RAID out of 250 GB disks using an add-on RAID controller
under Fedora Core 1 and 3 was _not_ good.  I found severe performance
problems that I could not work around no matter what file system was used
(ext2 was the best overall, but we went with ext3 because of the journaling
it provides).  The worst performance was seen when the LDM queue was on
the RAID:  latencies from idd.unidata.ucar.edu to the two test machines
that I built rapidly approached 3600 seconds.  Moving the LDM queue off
to a file system other than the RAID would drop the latencies to subsecond
values (were were ingesting ALL ".*" for these tests).  My gut feeling was
that RAID and Linux were not a good match.  I heard passionate arguments
from community members that external RAIDs attached to Linux systems were
great performers, but I never had a chance to test that since we did not
have an external RAID in-house.

Like others, I am _very_ curious about ZFS performance under Solaris.  We
are also looking into GFS use for toplevel ADDE/THREDDS servers like
motherlode.ucar.edu (aka adde.ucar.edu).

One other comment:  our experience with Fedora Core 6 and Fedora 7 does not
match what others have written.  Yes, doing an upgrade from one distribution to 
the
next is slow since we do full OS+development installations, but we have not
experienced any of the strange problems that are being reported.  I feel that
our experiences are significant since we are running FC6 and F7 on the
nodes in our idd.unidata.ucar.edu cluster in addition to staff desktops.

Cheers,

Tom
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Ticket Details
===================
Ticket ID: FVR-912211
Department: Support Platforms
Priority: Normal
Status: Closed