Earlier today, I was reading through a series of posts on another Linux list
about where you should put the journal file for a journaling filesystem such
as ext3, xfs, reiserfs, etc. Some argued that putting a journal file on a RAID
array was a sure way to have it not work in the event of any RAID corruption
-- that a journal file should be on a separate device.
Does anybody on this list have some reliable information about this? For
instance, is it "safe" to put the xfs journal on a RAID-0 array along with the
xfs
filesystem?
What about on a RAID 50 array (Software RAID-0 on top of 2 or more 3ware
Hardware RAID-5 arrays?)
What is the generally accepted practice for xfs journals in Linux. Are they
put on RAIDS along with the filesystem (especially if you are looking for very
high read/write speeds, i.e., > 200 MB/sec for writes and > 600 MB/sec for
reads). My experience with trying to put the journal on a separate (and much
slower) device is that it completely kills the performance of the RAID.
Andy Liebman
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