RE: [RE] Poorer performance with Raid0 then without?

Yeah, that's what I did that I described as
"I tried removing the third drive on the board (primary slave), no effect. "
This smells like a driver/software problem. I'd like to try a different
setup.
Is there some way to use "md type" RAID that uses /dev/md? instead of "dm
type" RAID that uses /dev/mapper/*?
 
Thanks!
 
Listbox
  _____  

From: James Olson [mailto:[email protected]] 
Sent: Monday, January 01, 2007 5:15 PM
To: ATARAID (eg, Promise Fasttrak, Highpoint 370) related discussions
Subject: [RE] Poorer performance with Raid0 then without?


So the dma settings are normal. My only other thought is what do you have on
/dev/hdf? Is that drive a slave with /dev/hde as the master? Can you run the
system with hde and hdg but without hdf and see if the raid0 performance
improves? 








---------[ Received Mail Content ]----------

Subject : [RE] Poorer performance with Raid0 then without?

Date : Mon, 1 Jan 2007 11:24:31 -0800

>From : "Listbox" <[email protected]>

To : <[email protected]>



Here is more hdparm data. It looks like bad news. 



Note: for whatever reason, /dev/md0 does not seem to be my RAID device. I 

set up my raid (via trial and error) with dmraid, and it gave me 

/dev/mapper/sil_agbgdgbjfhei. I have always felt there was something 

not-right about that. 

Second, the errors hdparm reports from -tT look significant. 

Finally, "Timing cached reads" are much lower then single drives. I don't 

know what this really means in a RAID context. 



I tried removing the third drive on the board (primary slave), no effect. 



Anyway, given the errors, is this a RAID software problem, or a piece of 

junk RAID adapter card? 



Thanks so much, folks. 



Listbox 

* * * * * * * * * * * 

* * * * * * * * * * * 



/dev/hde: 

multcount = 16 (on) 

IO_support = 0 (default 16-bit) 

unmaskirq = 0 (off) 

using_dma = 1 (on) 

keepsettings = 0 (off) 

readonly = 0 (off) 

readahead = 256 (on) 

geometry = 19457/255/63, sectors = 312581808, start = 0 



/dev/hdg: 

multcount = 16 (on) 

IO_support = 0 (default 16-bit) 

unmaskirq = 0 (off) 

using_dma = 1 (on) 

keepsettings = 0 (off) 

readonly = 0 (off) 

readahead = 256 (on) 

geometry = 19457/255/63, sectors = 312581808, start = 0 



* * * * * * * * * * * 

* * * * * * * * * * * 





hprarm -tT /dev/md0 

read() hit EOF - device too small 



/dev/md0: 

Timing buffered disk reads: read() hit EOF - device too small 

BLKFLSBUF failed: No such device 

HDIO_DRIVE_CMD(null) (wait for flush complete) failed: No such device 



hprarm -tT /dev/mapper/sil_agbgdgbjfhei 

/dev/mapper/sil_agbgdgbjfhei: 

Timing cached reads: HDIO_DRIVE_CMD(null) (wait for flush complete) 

failed: Inappropriate ioctl for device 

1288 MB in 2.00 seconds = 643.22 MB/sec 

Timing buffered disk reads: HDIO_DRIVE_CMD(null) (wait for flush complete) 

failed: Inappropriate ioctl for device 

284 MB in 3.01 seconds = 94.27 MB/sec 

* * * * * * * * * * * 

* * * * * * * * * * * 

* * * * * * * * * * * 

* * * * * * * * * * * 

dev/hda: 

Timing cached reads: 1668 MB in 2.00 seconds = 834.10 MB/sec 

Timing buffered disk reads: 88 MB in 3.05 seconds = 28.87 MB/sec 



/dev/hdb: 

Timing buffered disk reads: 

/dev/hdc: 

Timing cached reads: 1696 MB in 2.00 seconds = 847.36 MB/sec 

Timing buffered disk reads: 88 MB in 3.05 seconds = 28.82 MB/sec 



/dev/hde: 

Timing cached reads: 1680 MB in 2.00 seconds = 838.49 MB/sec 

Timing buffered disk reads: 168 MB in 3.03 seconds = 55.46 MB/sec 



/dev/hdf: 

Timing cached reads: 1688 MB in 2.00 seconds = 843.57 MB/sec 

Timing buffered disk reads: 164 MB in 3.00 seconds = 54.59 MB/sec 



/dev/hdg: 

Timing cached reads: 1696 MB in 2.00 seconds = 846.68 MB/sec 

Timing buffered disk reads: 162 MB in 3.03 seconds = 53.45 MB/sec 



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