18 messages in org.freebsd.freebsd-fsRAID-3 and RAID-4 (was: RAID1 Softwar...| From | Sent On | Attachments |
|---|---|---|
| Bagnara Stefano | Nov 6, 1998 8:35 am | |
| Christopher Nielsen | Nov 6, 1998 1:35 pm | |
| Greg Lehey | Nov 6, 1998 3:49 pm | |
| Greg Lehey | Nov 6, 1998 3:51 pm | |
| Christopher Nielsen | Nov 6, 1998 4:41 pm | |
| Bill Vermillion | Nov 6, 1998 4:41 pm | |
| Greg Lehey | Nov 7, 1998 1:35 am | |
| Bill Vermillion | Nov 7, 1998 5:31 am | |
| Greg Lehey | Nov 7, 1998 3:18 pm | |
| Kenneth D. Merry | Nov 7, 1998 10:08 pm | |
| Greg Lehey | Nov 7, 1998 11:08 pm | |
| Justin T. Gibbs | Nov 7, 1998 11:17 pm | |
| Bill Vermillion | Nov 8, 1998 3:29 am | |
| Eivind Eklund | Nov 8, 1998 4:59 am | |
| Greg Lehey | Nov 8, 1998 7:55 pm | |
| Greg Lehey | Nov 8, 1998 7:58 pm | |
| Justin T. Gibbs | Nov 8, 1998 10:17 pm | |
| Greg Lehey | Nov 8, 1998 10:25 pm |
| Subject: | RAID-3 and RAID-4 (was: RAID1 Software vs Hardware) | |
|---|---|---|
| From: | Greg Lehey (gr...@lemis.com) | |
| Date: | Nov 8, 1998 10:25:51 pm | |
| List: | org.freebsd.freebsd-fs | |
On Sunday, 8 November 1998 at 23:17:36 -0700, Justin T. Gibbs wrote:
On Sunday, 8 November 1998 at 0:17:36 -0700, Justin T. Gibbs wrote:
RAID 3 is still used, and is still useful. All of Pluto's products (see http://www.plutotech.com) use RAID 3. It works quite well for video data.
I suppose it gives you good throughput. But how do you handle the I/O load? Are you effectively delivering a single video stream?
RAID 3 is ideal when your data requests are always a multiple of the strip size.
I'm not sure we're talking about the same thing. In my book, RAID-3 is a RAID-4 with a stripe size of 1 byte. How do you define it?
RAID-3 confines parity to 1 member of the array. The size of the stripe is not a part of the specification. In the case of Pluto products, we usually use a stripe size of 1MB which implies a per-unit access of 1MB/N-1 (N being number of members in the RAID group).
This looks like RAID-4 to me. Where do you see the difference?
Greg
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