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milosn
n00b
Joined: 08 Jun 2002
Posts: 6
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 Posted: Tue Jul 08, 2003 12:40 am Post subject: software raid && UDMA |
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How much would performance of a 2 udma100 drives, in RAID0(striping) configuration, be downgraded in case they are pluged into mobo with udma66 controler?
Also udma66 means that max performance of the controller is 66MB/s. Is that on one chanel 66MB/s and second one 66MB/s, or IDE chanels divide this 66MB/s at any moment.
The drives max out on 35-40MB/s in hdparm test, 69MB/s on md0 device,so that made me wondering if i could plug them into udma66 mobo and have them in raid0 mode with no performance hit on controler side.
Regards |
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ctford0
l33t
Joined: 25 Oct 2002
Posts: 774
Location: Lexington, KY,USA
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| Posted: Tue Jul 08, 2003 8:03 am Post subject: |
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You would come very close to the same performance. ATA 100 isn't much faster as far as sustained transfer rate than ATA 66.
BTW, I get the following when running an 80 gig Maxtor HD with 8 megs cache.
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# hdparm -Tt /dev/hda
/dev/hda:
Timing buffer-cache reads: 128 MB in 1.14 seconds =112.78 MB/sec
Timing buffered disk reads: 64 MB in 1.28 seconds = 50.00 MB/sec
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Note that this was durning an NFS backup of another machine to this one, the load average at the time was almost 8.0, so these results could be a little low. This is actually better than I get on a Promise fastrack ata raid controller, running one drive at a time, at ATA 133.
Chris |
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bonsaikitten
Apprentice
Joined: 01 Jan 2003
Posts: 213
Location: Shanghai, China
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| Posted: Tue Jul 08, 2003 4:16 pm Post subject: |
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| Some Promise controllers only have the bandwith of one IDE-channel, I think the TX-2 is the faster one. So depending on your controller you could be limited to around 60 MB/s instead of ~70MB/s. I think that is not a significant performance degradation. And as far as I know the two channels on MoBos are independent. |
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Garbz
Apprentice
Joined: 02 Jul 2003
Posts: 260
Location: Brisbane, Australia
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| Posted: Wed Jul 09, 2003 2:44 am Post subject: |
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the performance of any raid will allways be the fastest speed of the slower drive by my knowledge providing they are on separate channels.
Hdparm a while back showed:
hde7 29mb/s
hdg2 44mb/s
md0 58mb/s
the partitions because of my gay setup (my own fault) are at the beginig of the hdg drive and the very end of the hde drive.
IBM Deathstar 40gb hdg
Seagate Baracuda IV 60gb hde
_________________
Every begining is another begining's end. |
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