ATA RAID-0 FYI-Did the Impossible.

Andre Hedrick (andre@linux-ide.org)
Mon, 31 Dec 2001 06:05:57 -0800 (PST)


TIOBENCH

No size specified, using 1792 MB
Size is MB, BlkSz is Bytes, Read, Write, and Seeks are MB/sec

File Block Num Seq Read Rand Read Seq Write Rand Write
Dir Size Size Thr Rate (CPU%) Rate (CPU%) Rate (CPU%) Rate (CPU%)
------- ------ ------- --- ----------- ----------- ----------- -----------
. 1792 4096 1 153.6 98.1% 0.897 0.91% 85.59 51.2% 3.399 1.95%
. 1792 4096 2 104.7 67.8% 1.080 1.00% 79.63 58.4% 3.437 3.29%
. 1792 4096 4 91.57 61.2% 1.292 1.24% 76.45 59.3% 3.471 3.40%
. 1792 4096 8 83.55 57.3% 1.480 1.39% 73.80 59.2% 3.455 3.26%

File './Bonnie.1089', size: 1073741824, volumes: 1
Writing with putc()... done: 9854 kB/s 100.0 %CPU
Rewriting... done: 65537 kB/s 52.2 %CPU
Writing intelligently...done: 109124 kB/s 51.0 %CPU
Reading with getc()... done: 9821 kB/s 99.9 %CPU
Reading intelligently...done: 167240 kB/s 97.6 %CPU
Seeker 1...Seeker 2...Seeker 3...start 'em...done...done...done...
---Sequential Output (nosync)--- ---Sequential Input-- --Rnd Seek-
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --04k (03)-
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
1*1024 9854 100.0 109124 51.0 65537 52.2 9821 99.9 167240 97.6 1504.4
6.4

hdparm -t /dev/md0

/dev/md0:
Timing buffered disk reads: 64 MB in 0.47 seconds =136.17 MB/sec

hde: 39102336 sectors (20020 MB) w/2048KiB Cache, CHS=38792/16/63, UDMA(100)
hdg: 39102336 sectors (20020 MB) w/2048KiB Cache, CHS=38792/16/63, UDMA(100)
hdi: 39102336 sectors (20020 MB) w/2048KiB Cache, CHS=38792/16/63, UDMA(100)
hdk: 39102336 sectors (20020 MB) w/2048KiB Cache, CHS=38792/16/63, UDMA(100)

/etc/raidtab

raiddev /dev/md0
raid-level 0
nr-raid-disks 4
persistent-superblock 0
chunk-size <snipped>

device /dev/hd<snipped>1
raid-disk 0
device /dev/hd<snipped>1
raid-disk 1
device /dev/hd<snipped>1
raid-disk 2
device /dev/hd<snipped>1
raid-disk 3

If you want your system to have this kind of performance, that raise hell
to get the patches adopted into the main kernel.

Regards,

Andre Hedrick
CEO/President, LAD Storage Consulting Group
Linux ATA Development
Linux Disk Certification Project

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