Messages in this thread | | | Date | Mon, 14 Aug 2000 16:01:55 -0400 | From | Giuliano Pochini <> | Subject | Elevator problem ? |
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Kernel 2.2.16 show very low disk performance on my magneto-optical drive. When I write large files it starts writing at its normal speed. After 10-20 sec. speed drops from 500KB/s to 30KB/s :-((((( I tried to change elevator tuning with the attached program I wrote (please tell me if there's something wrong) without success. The point is it starts writing only 2KB small block without any apparent reason. Another BIG problen is that when it starts crawling also write accesses to my harddisk became way slow. I have to wait a minute or so to copy a 100KB file !! And it's not a question of memory because it happens even if I still have 90MB free ram. I noted that both MO-drive and the HD have the same evevator-queue-ID. I think this is a bug, since they are completely unrelated devices which are attached to 2 different SCSI cards... The HD alone don't have this problem, so I think it's related with the slowness of the MO-drive, perhaps blocks ageing is wrong.... I don't know. I tried 2.2.6 and it works fine. I have no recent kernels prior 2.2.16 now, but I'll try soon.
Bye. Giuliano.
P.S. Why disksnever r/w blocks larger than 64KB ? This issue lowers raw disk speed by ~30%[unhandled content-type:application/octet-stream]
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