On Thu, 6 Mar 2008, Edward Ned Harvey wrote:
In nearly all situations, I'll recommend hardware raid controller, with
hotswappable hard drives, and at least raid 5 configuration. So you get the
performance & size benefit of a bunch of disks, with at least some
redundancy to prevent data loss during hardware failure.
My worry about hardware RAID controllers is what if it breaks? Would you
need to replace it with the same make, model, and firmware rev level to
recover your data? Or is there some compatibility across models within a
brand? We have several RAID controllers from 3Ware and RocketRaid, none
make any such claim in their documentation or online. Nor have I ever seen
any software that claimed to be able to recover data from hardware raid
arrays without the hardware.
Anyway, with multi-core processors, the CPU load from software raid is not
very important.
In case anyone on this list hasn't seen it, I posted some lessons we have
learned about storage at
http://www.nber.org/sys-admin/linux-nas-raid.html
Daniel Feenberg
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Scott R. Ehrlich
Sent: Thursday, March 06, 2008 6:58 PM
To: [email protected]
Subject: [BBLISA] Moving from RAID 0 to LVM RAID?
So I've learned a valuable RAID 0 lesson, and it fortunately was not a
major
catastrophy. I got lucky, and had a workable-enough backup on tape to
make the
user who needed some data happy.
Now, from the OS side, LVM is an option. Say the RAID controller only
allows
hardware striping or mirroring for logical volumes, but I want to use
more than
two disks, and I don't want the RAID 0 problem again.
When I get a replacement disk and build the system from the ground up
again, I
could, conceivably, use hardware RAID 1 for the OS on two disks, and
CentOS 5
64-bit's LVM for software RAID 5 (or maybe 1+0 if available) on the
remaining
for 4 disks, maybe 3 disks as active and the 4th as a hot spare?
I've never had much faith in software raid, since it is not hardware-
based, and
there would be a performance hit, but in this case, it could be an
option.
Insights from the OS-created RAID experience welcome.
Thanks again.
Scott
_______________________________________________
bblisa mailing list
[email protected]
http://www.bblisa.org/mailman/listinfo/bblisa
_______________________________________________
bblisa mailing list
[email protected]
http://www.bblisa.org/mailman/listinfo/bblisa
_______________________________________________
bblisa mailing list
[email protected]
http://www.bblisa.org/mailman/listinfo/bblisa
