Author: Robert Hyatt
Date: 06:51:34 02/21/03
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On February 21, 2003 at 05:31:35, Matt Taylor wrote: >On February 20, 2003 at 18:23:22, Robert Hyatt wrote: > ><snip> >>My cpus don't run blazing hot, although there is another significant performance >>difference >>in our boxes. I can copy 8 gigs of data in 30 seconds. That is important for >>chess endgames >>with tables. I don't think you can get 1/10th of that speed with IDE drives of >>any kind. >>But that is yet a different subject. ><snip> > >(2) Western Digital 80GB 8MB cache 7200 rpm >3ware 7000-2 RAID controller > >Buffered Read: 94 MB/sec >Sequential Read: 49 MB/sec >Random Read: 6 MB/sec > >Buffered Write: 87 MB/sec >Sequential Write: 58 MB/sec >Random Write: 12 MB/sec > >This would be 1.4 GB in 30 seconds. Nowhere near 8 GB, but it's more than 10%. >Also, this was done on an NT box using NTFS, and NTFS is notoriously slow. >Seeking all over a 7200 rpm drive really cripples the "sequential" speed. > >That is the low-end model RAID controller in 2-disk RAID-0. 8-disk RAID-0 is >pretty fast. They claim speeds up near 600 or 700 MB/sec in which case it would >be copying 18 GB in 30 seconds. The 7500-8 costs something like $350 or $250, I >believe. That array would be about $1,000. The 8500-8 is what I would use if >money were no object. > >-Matt I've got an 8-drive IDE raid array here we are playing with for backups, and it is _not_ fast. This is an 8 x 250gig device and no, I don't remember who made it as it isn't ours (ours = CIS) it was an evaluation device from our IT folks up the street. However, the random speed is more important than the sequential read for tablebases, and the 15K SCSI drives have 1/2 the latency of the best IDE drives so far that I have seen (7200 RPM). I'll run the 8 gig copy on this array monday to get a number, but when I tried it last time it took over 5 minutes total. Which is where I got my 10x number. Beware of claimed speeds also, as that is typically drive buffer to memory, which is not the same as copying large files where buffer means zero.
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