[Beowulf] RAID for home beowulf
hahn at mcmaster.ca
Sun Oct 4 23:28:52 PDT 2009
> the other nodes are to be diskless.. I have separated these partitions:
> /swap /boot / /var and /home. Is this ok?
I don't believe there is much value in separating partitions like this.
for instance, a swap partition has no advantage over a swap file,
and the latter is generally more convenient. separating /boot is
largely a vestige of quite old bioses which could not do 48b LBA
addressing (ie, deal with big disks.) separating /, /var and /home
is largely a matter of taste:
- separate /home means that you can blast / and /var when
you upgrade or change distros.
- separating / and /var means that something like syslog or
mail can never fill up the root partition. which is generally
not a serious issue anyway: if anything, this argues for putting
/tmp in a separate partition, but leaving /var inside /...
- more partitions (filesystems) means more time spent waiting
for disk heads to seek. remember that write activity on any fs
(modern, journaling) requires some synchronous writes, and
therefore can't be lazy-ified or elevator-scheduled when you have
I think it's always a good idea to minimize partitions, though we can
probably argue about how many is best. I suppose one factor in favor
of separate, purpose-specific filesystems is that they might be split
into different raid levels. for instance, /tmp might be raid0, perhaps
/var a >2 disk raid10 for write speed, and /home left on /, both under
raid6. but given that you don't want multiple filesystems competing
for access to the same disk(s), I'm skeptical of this approach...
in short, it's perfectly OK to use one big filesystem. or you can just
use the distro's default partitioning scheme. in the end it's not going
to make much difference.
regards, mark hahn.
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