On Thu, Nov 10, 2005 at 09:57:02AM -0800, lordSauron wrote: > On 11/10/05, Albert Dengg <[EMAIL PROTECTED]> wrote: > > well it has to map the raid device to the real discs...like with all > > raid levels > > > > also... > > raid 0 isnt really raid... > > raid means _redundant_ array of independet/inexpensive discs... > > and raid 0 isnt redundant at all > > I'm interested in RAID 0 b/c I want drive speed, not drive > reliability. I've got a full-tower ATX case which runs amazingly cool > and quiet, so I'm not concerned with my drives freaking out and > spontaniously dying. > > So the current installer does not support the motherboard's RAID, > which is slower, but what about setting up linux's kernel's RAID? Can > the current Sarge installer do that? > > Also, I know about RAID 0, 1, and 50, but what on earth is RAID 5 and > 6? I think RAID 5 has to do with networked JBODs, but I'm not sure...
RAID0 (not raid) is stripping data over multiple disks to increase performance. RAID1 is mirroring data across 2 disks to increase reliability (at the cost of half your disk space). RAID 3 4 and 5 are stripping with parity across multiple devices to increase speed and reliability, although it requries xor calculations liek there is no tomorrow and hence often is only done with a hardware xor engine for acceleration. Modern CPUs with good MMX/SSE/etc algorithms are not bad at it either though. Raid 5 stripes the parity data across the disks to avoid a heavy load on a single disk storing parity data. Raid 3 and 4 store the parity data on one device only. Costs you one disk worth of disk space out of your total space (so you can 700G if you have 8 * 100G drives in raid 3/4/5). RAID6 is RAID5 with ECC. It stores a second set of parity data to allow error correction. It costs you two disks worth of space out of the total (so you get 600G if you have 8 * 100G drives). It can I believe tolerate 2 disk failures without data loss (although at that point you get no error correction anymore). Supposedly from what I have seen, RAID10 is disks stripped, then mirror two identical size RAID0s, while RAID01 is disks mirrored, and then stripe the mirrors, and RAID50 is two RAID5s mirrored. Len Sorensen -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
