Ultra 320 in slow mode.

[Alexander Linkenbach]

Hi there
I've just reinstalled my system on a softraid1 on two Seagate Cheetahs (36GB
ST336607LW 68Pin Ultra320 SCSI) connected to an LSI21320-R.
When booting up the controller's bios reports that the devices are certified
for 80MB/s but should run at 320 once the OS has started.
However all I get is this:

mother:/home/alex # hdparm -t /dev/sda

/dev/sda:
Timing buffered disk reads: 168 MB in 3.11 seconds = 54.05 MB/sec
mother:/home/alex # hdparm -t /dev/sdb

/dev/sdb:
Timing buffered disk reads: 182 MB in 3.02 seconds = 60.18 MB/sec
mother:/home/alex # hdparm -t /dev/md0

/dev/md0:
Timing buffered disk reads: 200 MB in 3.00 seconds = 66.66 MB/sec

I was hoping to get something up to 640 actually as thhe drives are on
different channels and the only devices on each channel:
scsibus0:
0,0,0 0) 'SEAGATE ' 'ST336607LW ' '0008' Disk
0,1,0 1) *
0,2,0 2) *
0,3,0 3) *
0,4,0 4) *
0,5,0 5) *
0,6,0 6) *
0,7,0 7) *
scsibus1:
1,0,0 100) *
1,1,0 101) 'SEAGATE ' 'ST336607LW ' '0006' Disk
1,2,0 102) *
1,3,0 103) *
1,4,0 104) *
1,5,0 105) *
1,6,0 106) *
1,7,0 107) *

The module used by the kernel is mptspi.
SuSE 10.0 with
mother:/home/alex # cat /proc/version
Linux version 2.6.13-15-smp (geeko@buildhost) (gcc version 4.0.2 20050901
(prerelease) (SUSE Linux)) #1 SMP Tue Sep 13 14:56:15 UTC 2005
Dual Athlon MP 2600+ on Asus A7M266-D, 1GB Ram
(Remark: During installation I discovered in a painfully long stripping down
process that the LSI would not let me install with any other card in the
remaining 64bit slot. Simply froze during mk_initrd or later after starting
GRUB)
Any ideas how to speed this up?
How can I test the drives' speed under winxp (yes, have got it somewhere on
a drive in the machine, I think...) for comparison?

Help appreciated and a happy new year to all
alex

 

[Jean-David Beyer]

Hi there
I've just reinstalled my system on a softraid1 on two Seagate Cheetahs (36GB
ST336607LW 68Pin Ultra320 SCSI) connected to an LSI21320-R.
When booting up the controller's bios reports that the devices are certified
for 80MB/s but should run at 320 once the OS has started.
However all I get is this:

mother:/home/alex # hdparm -t /dev/sda

/dev/sda:
Timing buffered disk reads: 168 MB in 3.11 seconds = 54.05 MB/sec
mother:/home/alex # hdparm -t /dev/sdb

/dev/sdb:
Timing buffered disk reads: 182 MB in 3.02 seconds = 60.18 MB/sec
mother:/home/alex # hdparm -t /dev/md0

/dev/md0:
Timing buffered disk reads: 200 MB in 3.00 seconds = 66.66 MB/sec

I was hoping to get something up to 640 actually as thhe drives are on
different channels and the only devices on each channel:
scsibus0:
0,0,0 0) 'SEAGATE ' 'ST336607LW ' '0008' Disk
0,1,0 1) *
0,2,0 2) *
0,3,0 3) *
0,4,0 4) *
0,5,0 5) *
0,6,0 6) *
0,7,0 7) *
scsibus1:
1,0,0 100) *
1,1,0 101) 'SEAGATE ' 'ST336607LW ' '0006' Disk
1,2,0 102) *
1,3,0 103) *
1,4,0 104) *
1,5,0 105) *
1,6,0 106) *
1,7,0 107) *

The module used by the kernel is mptspi.
SuSE 10.0 with
mother:/home/alex # cat /proc/version
Linux version 2.6.13-15-smp (geeko@buildhost) (gcc version 4.0.2 20050901
(prerelease) (SUSE Linux)) #1 SMP Tue Sep 13 14:56:15 UTC 2005
Dual Athlon MP 2600+ on Asus A7M266-D, 1GB Ram
(Remark: During installation I discovered in a painfully long stripping down
process that the LSI would not let me install with any other card in the
remaining 64bit slot. Simply froze during mk_initrd or later after starting
GRUB)
Any ideas how to speed this up?
How can I test the drives' speed under winxp (yes, have got it somewhere on
a drive in the machine, I think...) for comparison?

Help appreciated and a happy new year to all
alex

If that bugs you, consider this:
# /sbin/hdparm -t /dev/sdd

/dev/sdd:
Timing buffered disk reads: 122 MB in 3.03 seconds = 40.26 MB/sec
# /sbin/hdparm -t /dev/sdc

/dev/sdc:
Timing buffered disk reads: 118 MB in 3.04 seconds = 38.82 MB/sec
# /sbin/hdparm -t /dev/sdb

/dev/sdb:
Timing buffered disk reads: 122 MB in 3.01 seconds = 40.53 MB/sec
# /sbin/hdparm -t /dev/sda

/dev/sda:
Timing buffered disk reads: 122 MB in 3.02 seconds = 40.40 MB/sec
# /sbin/hdparm -t /dev/hdb

/dev/hdb:
Timing buffered disk reads: 166 MB in 3.00 seconds = 55.33 MB/sec
# /sbin/hdparm -t /dev/hda

/dev/hda:
Timing buffered disk reads: 152 MB in 3.01 seconds = 50.50 MB/sec
#

The SCSI hard drives are all Maxtor 10,000 rpm Atlas III with 8 Megabytes
buffer in each.

The EIDE (100) drives are all Maxtor 7,200 rpm Diamond Max 9 with 8
Megabytes in each.

scsibus0:
0,0,0 0) 'MAXTOR ' 'ATLASU320_18_WLS' 'B120' Disk
0,1,0 1) 'MAXTOR ' 'ATLASU320_18_WLS' 'B120' Disk
0,2,0 2) 'MAXTOR ' 'ATLASU320_18_WLS' 'B120' Disk
0,3,0 3) 'MAXTOR ' 'ATLASU320_18_WLS' 'B120' Disk
0,4,0 4) *
0,5,0 5) *
0,6,0 6) *
0,7,0 7) *
scsibus1:
1,0,0 100) *
1,1,0 101) *
1,2,0 102) *
1,3,0 103) *
1,4,0 104) *
1,5,0 105) *
1,6,0 106) *
1,7,0 107) *
1,11,0 111) 'EXABYTE ' 'VXA-2 ' '2107' Removable Tape

The disk drives were essentially idle when I ran these.

 

[Alexander Linkenbach]

If that bugs you, consider this:
# /sbin/hdparm -t /dev/sdd

Well, I'm not saying that such thing is a real problem. But why spend over
2oo$ for Ultra 320 card when I might as well connect them to my six year
old Wide card?!
Pretty annoying this.
alex

 

[John-Paul Stewart]

Hi there
I've just reinstalled my system on a softraid1 on two Seagate Cheetahs (36GB
ST336607LW 68Pin Ultra320 SCSI) connected to an LSI21320-R.
When booting up the controller's bios reports that the devices are certified
for 80MB/s but should run at 320 once the OS has started.
However all I get is this:

mother:/home/alex # hdparm -t /dev/sda

/dev/sda:
Timing buffered disk reads: 168 MB in 3.11 seconds = 54.05 MB/sec
mother:/home/alex # hdparm -t /dev/sdb

/dev/sdb:
Timing buffered disk reads: 182 MB in 3.02 seconds = 60.18 MB/sec

These are normal results. 320 MB/sec is the *bus* speed. No single
disk can sustain that speed. (You can get the full 320 MB/sec from the
buffer but that's only 8 MB. The physical disk mechanism is what limits
*sustained* transfer rate.) 55-60 MB/sec seems about right for this
particular 36GB 10K RPM SCSI drive. The advantage of SCSI is that you
can have multiple disks on the same SCSI bus with no loss of
performance. In your case you could have as many as five of these disks
on the same SCSI bus, and all would operate at full speed.

You'll never get full bus speed out of any single disk. This applies
even to IDE and SATA disks. (Their interfaces are typically twice as
fast as a single disk.)

 

[Henrik Carlqvist]

When booting up the controller's bios reports that the devices are certified
for 80MB/s but should run at 320 once the OS has started.
However all I get is this:

mother:/home/alex # hdparm -t /dev/sda

/dev/sda:
Timing buffered disk reads: 168 MB in 3.11 seconds = 54.05 MB/sec
mother:/home/alex # hdparm -t /dev/sdb

/dev/sdb:
Timing buffered disk reads: 182 MB in 3.02 seconds = 60.18 MB/sec
mother:/home/alex # hdparm -t /dev/md0

/dev/md0:
Timing buffered disk reads: 200 MB in 3.00 seconds = 66.66 MB/sec

I was hoping to get something up to 640 actually as thhe drives are on
different channels and the only devices on each channel

It seems as if some explanation of different bandwidths are necessary:

Ultra 320 means that the SCSI bus is able to handle bandwidths up to 320
MB/s. If you SCSI controller is able to deliver data at this speed you
will reach that speed until the cache on the HD is full. According to the
specifications of your drive at
http://www.seagate.com/cda/products/discsales/enterprise/tech/1,1084,541,00.html
the size of the cache is 8 MB. So, if you are lucky you might be able to
transfer 8 MB in 0.025s. Once your cache is full the transfer speed is
limited by the speed of the disks. According to the same page, the average
formatted transfer rate is 59.9 MB/s so your performance numbers are
rather good.

The internal transfer rate depends on many things, the most important
thing is probably the rotation speed. Your 10 krpm disks are faster than
7200 rpm disks but they are slower than 15 krpm disks.

The next thing to be aware of is the bus speed of your PCI bus. A 32-bit
PCI bus running at 33 MHz are in theory capable of transfer rates up to
132 MB/s. In practice it is hard to get above half that speed. If your
SCSI card is on a 32 bit PCI bus that might explain why you don't get
better performance from your raid 0 system.

regards Henrik

 

[Alexander Linkenbach]

It seems as if some explanation of different bandwidths are necessary:

Ultra 320 means that the SCSI bus is able to handle bandwidths up to 320
MB/s. If you SCSI controller is able to deliver data at this speed you
will reach that speed until the cache on the HD is full. According to the
specifications of your drive at
http://www.seagate.com/cda/products/discsales/enterprise/tech/1,1084,541,00.html
the size of the cache is 8 MB. So, if you are lucky you might be able to
transfer 8 MB in 0.025s. Once your cache is full the transfer speed is
limited by the speed of the disks. According to the same page, the average
formatted transfer rate is 59.9 MB/s so your performance numbers are
rather good.

The internal transfer rate depends on many things, the most important
thing is probably the rotation speed. Your 10 krpm disks are faster than
7200 rpm disks but they are slower than 15 krpm disks.

The next thing to be aware of is the bus speed of your PCI bus. A 32-bit
PCI bus running at 33 MHz are in theory capable of transfer rates up to
132 MB/s. In practice it is hard to get above half that speed. If your
SCSI card is on a 32 bit PCI bus that might explain why you don't get
better performance from your raid 0 system.

regards Henrik

Thanks Henrik
learned a few lessons here...
Seems I have to be content with my speeds (It's a 64bit slot by the way).
Just wondering what's the point in having ultra320 drive then, if the
perfomance is limited by the rotation speed anyway.
alex

 

[JosephKK]

Hi there
I've just reinstalled my system on a softraid1 on two Seagate Cheetahs
(36GB ST336607LW 68Pin Ultra320 SCSI) connected to an LSI21320-R.
When booting up the controller's bios reports that the devices are
certified for 80MB/s but should run at 320 once the OS has started.
However all I get is this:

mother:/home/alex # hdparm -t /dev/sda

/dev/sda:
Timing buffered disk reads: 168 MB in 3.11 seconds = 54.05 MB/sec
mother:/home/alex # hdparm -t /dev/sdb

/dev/sdb:
Timing buffered disk reads: 182 MB in 3.02 seconds = 60.18 MB/sec
mother:/home/alex # hdparm -t /dev/md0

/dev/md0:
Timing buffered disk reads: 200 MB in 3.00 seconds = 66.66 MB/sec

I was hoping to get something up to 640 actually as thhe drives are on
different channels and the only devices on each channel:
scsibus0:
0,0,0 0) 'SEAGATE ' 'ST336607LW ' '0008' Disk
0,1,0 1) *
0,2,0 2) *
0,3,0 3) *
0,4,0 4) *
0,5,0 5) *
0,6,0 6) *
0,7,0 7) *
scsibus1:
1,0,0 100) *
1,1,0 101) 'SEAGATE ' 'ST336607LW ' '0006' Disk
1,2,0 102) *
1,3,0 103) *
1,4,0 104) *
1,5,0 105) *
1,6,0 106) *
1,7,0 107) *

The module used by the kernel is mptspi.
SuSE 10.0 with
mother:/home/alex # cat /proc/version
Linux version 2.6.13-15-smp (geeko@buildhost) (gcc version 4.0.2 20050901
(prerelease) (SUSE Linux)) #1 SMP Tue Sep 13 14:56:15 UTC 2005
Dual Athlon MP 2600+ on Asus A7M266-D, 1GB Ram
(Remark: During installation I discovered in a painfully long stripping
down process that the LSI would not let me install with any other card in
the remaining 64bit slot. Simply froze during mk_initrd or later after
starting GRUB)
Any ideas how to speed this up?
How can I test the drives' speed under winxp (yes, have got it somewhere
on a drive in the machine, I think...) for comparison?

Help appreciated and a happy new year to all
alex

Standard 32-bit 33MHz PCI bus tops out at 133 MB/s. Most common current
systems have 32-bit 33/64MHz which tops out at 266 MB/s. Since you seem to
have 64-bit slot(s) they are often one or tother but not both at the same
time. Read your mobo documentation. If you have (as it seems) 64-bit
64MHz slot it should be able to handle 533 MB/s bursts. Bulk throughput
is limited by other things as well, mostly by rotational rate (maximum
number of blocks per second past the read head), then memory bandwidth
contention, PCI bus congestion, disk command overhead, disk adapter
overhead, disk drive electronics overhead, etc., Assuming 10000 RPM, 255
sectors (quite artificially low but the drive remaps), 512 byte blocks (MS
compatibility standard) we get about 21 MB/s for max for single drive
sustained read speeds. Added to that, is that performance will vary by
where on the disk drive you are (varying actual physical sectors per track
by track/cylinder number). Just the same, something ain't right, you
should have seen at least 100 MB/s from md0.

 

[iforone]

Hi there
I've just reinstalled my system on a softraid1 on two Seagate Cheetahs (36GB
ST336607LW 68Pin Ultra320 SCSI) connected to an LSI21320-R.
When booting up the controller's bios reports that the devices are certified
for 80MB/s but should run at 320 once the OS has started.
However all I get is this:

mother:/home/alex # hdparm -t /dev/sda

/dev/sda:
Timing buffered disk reads: 168 MB in 3.11 seconds = 54.05 MB/sec
mother:/home/alex # hdparm -t /dev/sdb

/dev/sdb:
Timing buffered disk reads: 182 MB in 3.02 seconds = 60.18 MB/sec
mother:/home/alex # hdparm -t /dev/md0

/dev/md0:
Timing buffered disk reads: 200 MB in 3.00 seconds = 66.66 MB/sec

I was hoping to get something up to 640 actually as thhe drives are on
different channels and the only devices on each channel:
scsibus0:
0,0,0 0) 'SEAGATE ' 'ST336607LW ' '0008' Disk
0,1,0 1) *
0,2,0 2) *
0,3,0 3) *
0,4,0 4) *
0,5,0 5) *
0,6,0 6) *
0,7,0 7) *
scsibus1:
1,0,0 100) *
1,1,0 101) 'SEAGATE ' 'ST336607LW ' '0006' Disk
1,2,0 102) *
1,3,0 103) *
1,4,0 104) *
1,5,0 105) *
1,6,0 106) *
1,7,0 107) *

The module used by the kernel is mptspi.
SuSE 10.0 with
mother:/home/alex # cat /proc/version
Linux version 2.6.13-15-smp (geeko@buildhost) (gcc version 4.0.2 20050901
(prerelease) (SUSE Linux)) #1 SMP Tue Sep 13 14:56:15 UTC 2005
Dual Athlon MP 2600+ on Asus A7M266-D, 1GB Ram
(Remark: During installation I discovered in a painfully long stripping down
process that the LSI would not let me install with any other card in the
remaining 64bit slot. Simply froze during mk_initrd or later after starting
GRUB)
Any ideas how to speed this up?
How can I test the drives' speed under winxp (yes, have got it somewhere on
a drive in the machine, I think...) for comparison?

Help appreciated and a happy new year to all
alex

typically (in winpoop anyway) - ATTO utilities are the way most
benchmark their HDDs
<http://www.digidesign.com/download/storage/>
I'm not sure if there's any type of licensing or trial version - or
whatever, since i don't use Xpoop, but i just d/l the tools (ZIP) from
the site above. I don't know what the equivalent is in Linux.

 

[Hans-Juergen Lange]

Hi there
I've just reinstalled my system on a softraid1 on two Seagate Cheetahs (36GB
ST336607LW 68Pin Ultra320 SCSI) connected to an LSI21320-R.
When booting up the controller's bios reports that the devices are certified
for 80MB/s but should run at 320 once the OS has started.
However all I get is this:

mother:/home/alex # hdparm -t /dev/sda

/dev/sda:
Timing buffered disk reads: 168 MB in 3.11 seconds = 54.05 MB/sec
mother:/home/alex # hdparm -t /dev/sdb

/dev/sdb:
Timing buffered disk reads: 182 MB in 3.02 seconds = 60.18 MB/sec
mother:/home/alex # hdparm -t /dev/md0

/dev/md0:
Timing buffered disk reads: 200 MB in 3.00 seconds = 66.66 MB/sec

I was hoping to get something up to 640 actually as thhe drives are on
different channels and the only devices on each channel:
scsibus0:
0,0,0 0) 'SEAGATE ' 'ST336607LW ' '0008' Disk
0,1,0 1) *
0,2,0 2) *
0,3,0 3) *
0,4,0 4) *
0,5,0 5) *
0,6,0 6) *
0,7,0 7) *
scsibus1:
1,0,0 100) *
1,1,0 101) 'SEAGATE ' 'ST336607LW ' '0006' Disk
1,2,0 102) *
1,3,0 103) *
1,4,0 104) *
1,5,0 105) *
1,6,0 106) *
1,7,0 107) *

The module used by the kernel is mptspi.
SuSE 10.0 with
mother:/home/alex # cat /proc/version
Linux version 2.6.13-15-smp (geeko@buildhost) (gcc version 4.0.2 20050901
(prerelease) (SUSE Linux)) #1 SMP Tue Sep 13 14:56:15 UTC 2005
Dual Athlon MP 2600+ on Asus A7M266-D, 1GB Ram
(Remark: During installation I discovered in a painfully long stripping down
process that the LSI would not let me install with any other card in the
remaining 64bit slot. Simply froze during mk_initrd or later after starting
GRUB)
Any ideas how to speed this up?
How can I test the drives' speed under winxp (yes, have got it somewhere on
a drive in the machine, I think...) for comparison?

Help appreciated and a happy new year to all
alex

Hello,

the interface has 320MB/sec not the disks itselfs. Have a look at the
manufacturers home pages for the data transfer rate. I think around
60MB/sec is fast.
You use one controller. Are you sure that it is capable of accessing
both channels synchronously? How much time get lost on sending the SCSI
request to the controller and than to the drive?
These are all things that are involved in the real data transfer rate.

BR
Hans-Juergen Lange

 

[John Murtari]

Hi there
I've just reinstalled my system on a softraid1 on two Seagate Cheetahs (36GB
ST336607LW 68Pin Ultra320 SCSI) connected to an LSI21320-R.
When booting up the controller's bios reports that the devices are certified
for 80MB/s but should run at 320 once the OS has started.
However all I get is this:

mother:/home/alex # hdparm -t /dev/sda

/dev/sda:
Timing buffered disk reads: 168 MB in 3.11 seconds = 54.05 MB/sec
mother:/home/alex # hdparm -t /dev/sdb

/dev/sdb:
Timing buffered disk reads: 182 MB in 3.02 seconds = 60.18 MB/sec
mother:/home/alex # hdparm -t /dev/md0

/dev/md0:
Timing buffered disk reads: 200 MB in 3.00 seconds = 66.66 MB/sec

Okay, you may have already gotten a reply, but the
320 rate is a bus maximum -- you would never see that on an
extended transfer from a drive (they can't keep up).

We have some 80 pin Seagate 15K.3 drives in a Dell
server with LSI chipset and see some slightly better numbers
than yours, but not much different. You are probably quite
fine.

Best regards!
--
John
___________________________________________________________________
John Murtari Software Workshop Inc.
jmurtari@following domain 315.635-1968(x-211) "TheBook.Com" (TM)
http://thebook.com/

 

[Alexander Linkenbach]

Thanks to everyone for the information. Learned something again.
alex