Messages in this thread | | | Date | Sun, 9 Dec 2001 20:32:57 +0100 (CET) | From | Roy Sigurd Karlsbakk <> | Subject | Re: software raid issues -- possible kernel I/O problem? |
| |
> <snip /> > So, my observations are as follows: > > 1) It seems as though I can't get aggregate burst speeds up above about > 100MB/s no matter what I do, even when it's on separate interfaces with > separate IRQs. Is this running into the limitation of the PCI bus? I'm > also somewhat confused as to how my old ata33 drive managed to score > nearly 100MB/s burst speed, as well as how some people are claiming > scores of 160MB/s on a ata100 drive (and why I'm not getting that on > mine).
The 100MB/s is probably the PCI bus, yes. The theoretical limit of a 32bit,33MHz PCI bus is 33^6*32/8 = 132.000.000 = ~ 125MB/s. In practice, there's always some overhead.
An ATA33 drive can't go over 33MB/s, as the bus don't deliver any more. an ATA100 bus can give you 100MB/s, but there is currently no drive available that can give you that. The fastest drive I've read about, is the Western Digital WD1200BB (120 gig). They brag about pushing 525Mbit/s from buffer to disk. That's some 65 megs per sec, which is pretty amazing.
roy
-- Roy Sigurd Karlsbakk, MCSE, MCNE, CLS, LCA
Computers are like air conditioners. They stop working when you open Windows.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |