[lug] Swap space, /boot and RAID and LVM

[Hugh Brown]

Elyse M. Grasso wrote:
> My big server is now up and running, (and being loaded with a bunch of stuff 
> from one of the servers at my office, since I have the space and we've had 
> some problems with backup/restore reliability.)
> 
> I'm currently running Fedora 7. (I still kind of miss KRUD, though). 
> 
> I have 4 physical hard drives, two dual core Opterons, 4 gigs of ram in two 
> dual channel banks.
> 
> I'm going to start playing with different LVM and RAID configurations.  I 
> think I eventually want LVM on top of RAID 10, partly to get maximum 
> experience with the admin tools.  
> 
> I've been googling about RAID and LVM and found enough information to be 
> confusing (probably because some of it is fairly old and may be obsolete). 
> Pointers to current, reliable docs would be appreciated.
> 
> /boot is not LVM-able but I have seen some references to RAIDing it
> 
>  I notice that there seems to be some debate about the advisability and safety 
> of RAIDing swap. Fedora put swap in an LVM volume, so I assume that is safe. 
> 
> I also noticed that the swap created by anaconda is only (!) 1.94 Gigs. I know 
> at one time it was recommended that swap space should equal physical memory. 
> Is that no longer recommended with very large memories? (I haven't had time 
> to read the latest installment of the memory series on LWN yet today). 
> 
> The server is going to be used (among other things) for testing build 
> automation tools, with some virtual machines loaded so I can test them in 
> different environments. Probably with at least one windows XP guest.
> 
> Opinions: should I increase the swap while I am thrashing the disk 
> partitioning? 
> 
> 
> Is anyone else going to MileHiCon this weekend?


We've got a smaller server at work that has /boot on /dev/md0 and LVM on 
  /dev/md2 and it's been running that way for a year or more.  It's a 
box running vmware.  We found that the disk speed has been a major 
bottleneck for vmware on that system.

This is what I found a few months ago when trying to understand recent 
swap recommendations: 
http://www.redhat.com/docs/manuals/enterprise/RHEL-5-manual/Deployment_Guide-en-US/ch-swapspace.html

Hugh