[Beowulf] RAID for home beowulf

Tomislav Maric tomislav.maric at gmx.com
Mon Oct 5 06:19:01 EDT 2009


Mark Hahn wrote:
>> 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
>  	multiple partitions.
> 
> 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.
> 

Thank you very much for the info. There so much of this stuff that's
totally new to me. I think I'm going to feel very lucky if I ever get
this thing to work properly.

Best regards,
Tomislav
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