Re: limits on raid
From: <hidden>
Date: 2007-06-18 18:43:30
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On Mon, 18 Jun 2007, Lennart Sorensen wrote:
On Mon, Jun 18, 2007 at 11:12:45AM -0700, david@lang.hm wrote:quoted
simple ultra-wide SCSI to a single controller.Hmm, isn't ultra-wide limited to 40MB/s? Is it Ultra320 wide? That could do a lot more, and 220MB/s sounds plausable for 320 scsi.
yes, sorry, ultra 320 wide.
quoted
I didn't realize that the rate reported by /proc/mdstat was the write speed that was takeing place, I thought it was the total data rate (reads + writes). the next time this message gets changed it would be a good thing to clarify this.Well I suppose itcould make sense to show rate of rebuild which you can then compare against the total size of tha raid, or you can have rate of write, which you then compare against the size of the drive being synced. Certainly I would expect much higer speeds if it was the overall raid size, while the numbers seem pretty reasonable as a write speed. 4MB/s would take for ever if it was the overall raid resync speed. I usually see SATA raid1 resync at 50 to 60MB/s or so, which matches the read and write speeds of the drives in the raid.
as I read it right now what happens is the worst of the options, you show the total size of the array for the amount of work that needs to be done, but then show only the write speed for the rate pf progress being made through the job. total rebuild time was estimated at ~3200 min David Lang