> > Hardware failure protection. > > If that's it then go with software RAID. > > The big problem with hardware RAID is that generally the disks are in a > proprietary format. If the card dies, you have to get *the exact same > type of card* in order to recover your data.
So? > Because, if you have a RAID 1 setup you can just pull half the disks > every week/month/bimonth and let the system rebuild. For most small > companies, this is the solution I recommend as you can buy quite a lot > of disks for the same price as a tape drive. Only works for small companies, but the idea's interesting. I myself am going for raid5, so... > > 1. Try expanding a raid10 by adding drives. > > 2. array cap on 5: (n-1)*disk cap > > array cap on 10: 50% of overall disk cap. in other words 50% loss. > > Yes. So? Disks are cheap and Raid 10 has a pretty nice boost for read > performance. 6x250GB in raid5 is 360 bucks for disks and gets me 1.25TB. 1.25TB in raid10 - your turn. Point 1 still applies. > However, if you are this cost sensitive, go with software RAID. I am indeed. It's for me, not company. (I'd rather not sell softraids with ATA disks to a customer.) > Yeah, *maybe* with 10-12 disks. Personally, I don't buy it. I note > that TekRam (the original supplier of those cards) doesn't seem to list > transfer rate. My guess is that they don't keep up. In addition, most > disks are sitting in the 40-60 MiB/sec range for platter transfer rate. > I think some of the latest are just starting to crack 80MiB/sec. Hm, they advertise that - dunno about law over there but here you gotta keep what you promise. Fine print, alright. But even if they only reach half that's a lot. I'll email Areca about this for fun. I'll post here if I get replies. > > If you were unclever enough to buy all the same disks from the same > > manufacturing date... yes. > > Not completely. Perhaps your enclosure got hot because one disk was > generating an unusual amount of heat. Perhaps two spindles stuck when > you powered the system down. I have seen lots of reasons. > > Go with a software RAID solution. Especially since I think you could > run in RAID 6 which would give you multiple disk failure protection > without sacrificing 50% of your disk space. Yes, RAID6 is tempting. Initially I would have only 50% of the disk's cap since I'd start with 4 drives but everyone can do the math when disk number grows. I'll probably spend another couple of weeks deciding what to do :) Dex -- -----BEGIN GEEK CODE BLOCK----- Version: 3.12 GCS d--(+)@ s-:+ a- C+++(++++) UL+>++++ P+>++ L+++>++++ E-- W++ N o? K- w--(---) !O M+ V- PS++(+) PE(-) Y++ PGP t++(---)@ 5 X+(++) R+(++) tv--(+)@ b++(+++) DI+++ D G++ e* h>++ r%>* y? ------END GEEK CODE BLOCK------ http://www.stop1984.com http://www.againsttcpa.com -- [email protected] http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-list
