From: centos-bounces@centos.org [mailto:centos-bounces@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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