Messages in this thread | | | Date | Tue, 09 Mar 2004 15:22:32 -0500 | From | Bill Davidsen <> | Subject | Re: questions about io scheduler |
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Mike Fedyk wrote: > Timothy Miller wrote: > >> >> >> Mike Fedyk wrote: >> >>> Nick Piggin wrote: >>> >>>> >>>> >>>> Kyle Wong wrote: >>>> >>>>> 2. Does io scheduler works with md RAID? Correct me if I'm wrong, >>>>> io-schedular <--> md driver <--> harddisks. >>>>> >>>>> >>>> >>>> It goes md driver -> io schedulers -> hard disks. >>> >>> >>> >>> >>> There is an IO scheduler per disk. >>> >>> So MD submits the data to each disk through the IO scheduler. >>> >>> This allows you to have the heads on each disk in the array at >>> different locations, and helps keep response times lower for seeky >>> loads. >> >> >> >> Say you've got a RAID1. In this case, MD could send the read request >> to either device. How does it decide which one to use? > > > The one with the drive head closest to the data.
Or hopefully the one not in use if one is busy...
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