I am happy I chose software RAID
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| Author | Content |
|---|---|
| Sander_Marechal Jul 15, 2008 11:01 PM EDT |
Remember about a half a year ago when I was contemplating between hardware RAID and software RAID? I am so happy with my software RAID now. I decided to kick out my ProLiant server because it eats almost 2500 KWh per year. I've set my eye on a small and cheap Dell T105. Only problem: No PCI-X slot so I can't put my 3ware card in it. Whatever would I have done if I had chosen for hardware RAID. Now I can simply move the disks to the new server (when it arrives) and count on mdadm to keep my array going :-) Software RAID has significant advantages over hardware RAID. The article only talks about performance and whether it justifies the cost of a hardware RAID card. You should not be looking just at the cost of the card but also about the cost of any future upgrades. If I had used hardware RAID it would have cost me $500 more to get a new server (either to get an expensive 3ware card that runs PCIe, or to get a more expensive T300 server that does have a PCI-X slot). |
| techiem2 Jul 16, 2008 9:32 AM EDT |
Yeah, I use software raid on my fileserver (can't afford one of them fancy high end raid controllers anyway).
I also have an "old" Dell Poweredge 2500c I'm setting up for the church here that I switched over from hardware raid to software raid.
While hardware raid is probably faster and such, it's just not as flexible.
Maybe it's different with the $$$$$ controllers, but the raid on the Poweredge will only let you raid full disks.
I love software raid because I can raid pretty much anything I want in any way I want, like using a partition on a disk for part of an array, while leaving the rest of the disk for other use (I do this on my fileserver). For example on my fileserver I have: Quoting: Standard mirror of 2 80GB disks. And also Quoting: cthulhu ~ # mdadm --detail /dev/md1 /dev/md1: Version : 00.90.03 Creation Time : Sat Feb 9 14:39:44 2008 Raid Level : raid0 Array Size : 40087296 (38.23 GiB 41.05 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 1 Persistence : Superblock is persistentStriping of 2 disk partitions. /dev/sdb is actually a 30GB disk, but I'm using 20GB for this array and the other 10GB as a separate partition. And yes, I know that I could have just raided the complete disks together and then partitioned the md into 2 parts, but I didn't know that at the time, and this demonstrates the flexibility of software raid anyway. And all of this is done with parts I have been given/have salvaged over the years (the server itself is an old Celeron 766 at the moment), except for the Promise Ultra133-TX2 controller for the raid disks and the Netgear Gigabit NIC (which will be replaced soon with an Intel Pro 1000 when I get around to swapping stuff out around the lan). |
| Sander_Marechal Jul 16, 2008 2:15 PM EDT |
Quoting:Maybe it's different with the $$$$$ controllers, but the raid on the Poweredge will only let you raid full disks. Even my high-end expensive 3ware only RAIDs full disks. This can be a problem when you loose a disk and don't have a spare one of the exact same brand and model. If you use a different one, the number of blocks may be slightly different. Not a problem if the new disk is a few blocks larger, but if it's a few blocks smaller you're looking at shrinking and rebuilding your entire RAID array. That's one of the main reasons I went with software RAID back then. I don't have the money to buy more identical disks and keep them around as spares "just in case". |
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