[CentOS] new "large" fileserver config questions

Tue Oct 2 03:39:19 UTC 2012
Keith Keller <kkeller at wombat.san-francisco.ca.us>

Hi all,

I was recently charged with configuring a new fairly large (24x3TB
disks) fileserver for my group.  I think I know mostly what I want to do
with it, but I did have two questions, at least one of which is directly
related to CentOS.

1) The controller node has two 90GB SSDs that I plan to use as a
bootable RAID1 system disk.  What is the preferred method for laying
out the RAID array?  I found this document on the wiki:


But that seems like it's somewhat nonstandard.  From what I've read in
the RHEL6 docs, it seems like the anaconda-supported RAID1 install is
the alternative that the wiki suggests, partitioning the disk and adding
the partitions to the appropriate RAID1 array.

So, is there a happy medium, where anaconda more directly supports the
partitionable RAID1 install method?  And if so, what are the drawbacks
to such a configuration?  The wiki talks about the advantages but
doesn't really address any disadvantages.

2) With large arrays you often hear about "aligning the filesystem to
the disk".  Is there a fairly standard way (I hope using only CentOS
tools) of going about this?  Are the various mkfs tools smart enough to
figure out how an array is aligned on its own, or is sysadmin
intervention required on such large arrays?  (If it helps any, the disk
array is backed by a 3ware 9750 controller.  I have not yet decided how
many disks I will use in the array, if that influences the alignment.)


kkeller at wombat.san-francisco.ca.us