Messages in this thread |  | | | Date | Fri, 24 Aug 2001 10:14:39 -0700 | | From | Daryll Strauss <> | | Subject | Re: software raid does not do parallel reads under 2.4? |
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On Fri, Aug 24, 2001 at 07:01:40PM +0200, Wilfried Weissmann wrote:
> I experienced some performance loss when moving from kernel 2.4.4 to > 2.4.7-ac3 regarding ide harddisks. I am useing the hpt ataraid driver > which does pretty much the same thing as the md disk striping driver. > I/O speed of the raid volume is about as fast as accessing a single > drive. > There were a lot of ide reports some time ago. Maybe they where problems > with concurrent I/O operations...?
I'm seeing similar behavior with SCSI. I've got two SCSI channels. If I run two dd's each talking to disks on different channels, I get 2x disk bandwidth. If I run two dd's talking to disks on the same channel I get 1x disk bandwidth. This is with 2.4.9, but I haven't isolated which kernel versions cause this.
This system has 8 U160 disks spread over 2 U160 channels and it hasn't been deployed yet, so if I can help with testing, let me know.
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