[CentOS] OT: Suggestions for RAID HW for 2 SATA drivesin DellPowerEdge SC

[Ross S. W. Walker]

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

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