On Sunday, 29 October 2006 at 23:05:32 -0800, R. B. Riddick wrote: > --- Greg 'groggy' Lehey <[EMAIL PROTECTED]> wrote: >> "Sufficiently large data blocks" equates to several megabytes. >> Currently MAXPHYS, the largest transfer request that would get to the >> bio layer, is 131072 bytes. This would imply a stripe size of not >> more than 32 kB for a five disk array, which is unrealistically small. >> >> I did consider this optimization, but it would only work if Vinum were >> first to buffer multiple requests, and there are all sorts of >> reliability issues there. For example, you'd have to lie about the >> first few requests that were only buffered and not actually sent out >> to disk. Possibly it should be done anyway. >> > I did it that way in my graid5 class: > http://home.tiscali.de/cmdr_faako/geom_raid5.tbz
I would have taken a look at it if the sources had been directly web viewable. > The source might look somehow incomprehensible, Heh. I know the feeling :-) > but it seems to be quite stable (on amd64 and i386)... > > > I tried to benchmark with a 3 disk array: > Single disk: 30MB/sec write speed > graid5 device: 20MB/sec write speed Can you give more details? Stripe size, request size, number of concurrent accessors, etc.? > I would be interested in other benchmarks about it. Try rawio. Greg -- See complete headers for address and phone numbers.
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