[CentOS] OT: Suggestions for RAID HW for 2 SATA drivesin DellPowerEdge SC
Ross S. W. Walker
rwalker at medallion.com
Fri Aug 31 13:21:32 UTC 2007
From: centos-bounces at centos.org
[mailto:centos-bounces at centos.org] On Behalf Of Feizhou
>
>
> > About 10 seconds after I started this thread, I remembered
> a long discussion about
> > RAID, SATA, etc., 2 or 3 months ago. I think that Feizhou
> (?) strongly recommended
> > going with Software RAID in CentOS. I will search for that
> and do a lot of
> > reading. RAID 1 for mirroring is what I want. Lanny
>
> Whoa there!
>
> Hardware raid + battery backed up memory cache in raid 1,10
> mode is hard
> to beat with software raid and hardware raid offers data integrity
> guarantee beyond software raid.
>
> If you were planning a huge array especially a raid5 array, then
> software raid may be better. Hardware RAID cards all come with memory
> caches now so their throughput is no longer limited.
>
> Another route you can go is getting a PCI/PCIe/PCI-X BBU
> RAM/NVRAM card
> to put an external journal on to speed up fsync performance for
> filesystems like ext3 over software raid since these cards
> can go beyond
> 1GB of memory unlike hardware raid cards that usually max out
> at 256MB.
What are some of these BBU NVRAM cards that I keep hearing people
talk about? I would love to check them out.
> Software RAID is also good if you need to be able to transfer
> the disks
> to another box that does not have a hardware raid controller
> or the same
> controller.
>
> Weigh these in your decision. :-)
For 2 SATA hard disks used for the OS I think HW RAID is overkill.
Besides I do not believe the PERC 5IR has BBU cache, that
controller is really only meant as a simple RAID1 controller for
the OS.
If you use HW RAID you will need to install the manufacturer's
software for monitoring it for a hard disk failure.
If you wanted to add additional storage, say a SAS/SATA enclosure
of 15 disks, then I would definitely invest in a HW RAID card for
that!
-Ross
______________________________________________________________________
This e-mail, and any attachments thereto, is intended only for use by
the addressee(s) named herein and may contain legally privileged
and/or confidential information. If you are not the intended recipient
of this e-mail, you are hereby notified that any dissemination,
distribution or copying of this e-mail, and any attachments thereto,
is strictly prohibited. If you have received this e-mail in error,
please immediately notify the sender and permanently delete the
original and any copy or printout thereof.
More information about the CentOS
mailing list