SEO

Helo.
Machine p510
OSLEVEL 5.3

I have an 16 Bit LVD SCSI Disk Drive (73400 MB)
Disk machine Type and Model......ST373307LC (SEAGATE)

If a get the same disk ST 373307 LC but from Seagate
not from IBM it is recognized as "Other SCSI disk".
That's OK - I understand this.

Read performace is the same for both disks.
It is about 70 M/sec.

But Write performance for ST373307LC from Seagate
is unacceptable:

For ST373307LC from IBM transfer rate is ca 60 MB/sec.

For ST373307LC fropm SEAGATE is ca 16 MB/sec.

1. Why?
2. Can we handle this (increase performance for non ibm disks?).

by the way:

I have done a test:
I have added (using smit) ST373307LC from IBM
as Other scsi disk and performance was just like
ST373307LC From seagate (very small).

If I have added 16 Bit LVD SCSI Disk Drive (73400 MB)
buf not from seagate but from Hitachi HUS103073FL3800
as Other scsi disk it was an error.
This dosk works only as "16 Bit LVD SCSI Disk Drive (73400 MB)"

with regards
grzegorz

gkal.USUNTO@kalasoft.com.pl wrote:
> Helo.
> Machine p510
> OSLEVEL 5.3
>
....
> But Write performance for ST373307LC from Seagate
> is unacceptable:
>
> For ST373307LC from IBM transfer rate is ca 60 MB/sec.
>
> For ST373307LC fropm SEAGATE is ca 16 MB/sec.
>
> 1. Why?

Please post a
$ lsattr -El hdiskN

for each disk
hth
Hajo

Hajo Ehlers wrote:
> gkal.USUNTO@kalasoft.com.pl wrote:
>> Helo.
>> Machine p510
>> OSLEVEL 5.3
>>
> ...
>> But Write performance for ST373307LC from Seagate
>> is unacceptable:
>>
>> For ST373307LC from IBM transfer rate is ca 60 MB/sec.
>>
>> For ST373307LC fropm SEAGATE is ca 16 MB/sec.
>>
>> 1. Why?
>
> Please post a
> $ lsattr -El hdiskN
>
> for each disk
> hth
> Hajo
>
DISK0 (Firmware IBM)


U787E.001.AAA3763-P1-T11-L4-L0 16 Bit LVD SCSI Disk Drive (73400 MB)

Manufacturer................IBM
Machine Type and Model......ST373307LC
FRU Number..................00P3072
ROS Level and ID............4335304A
Serial Number...............000869AC
EC Level....................H12094
Part Number.................00P2672
Device Specific.(Z0)........000003129F00013E
Device Specific.(Z1)........0812C512
Device Specific.(Z2)........0002
Device Specific.(Z3)........04245
Device Specific.(Z4)........0001
Device Specific.(Z5)........22
Device Specific.(Z6)........H12094

# lsattr -l hdisk0 -E
PCM PCM/friend/scsiscsd Path Control Module False
algorithm fail_over Algorithm True
dist_err_pcnt 0 Dist. Error Perc. True
dist_tw_width 50 Dist. Error Sample Time True
hcheck_interval 0 Health Check Interval True
hcheck_mode nonactive Health Check Mode True
max_transfer 0x40000 Maximum TRANSFER Size True
pvid 00c329ff702ead3c(cut) Physical volume id. False
queue_depth 3 Queue DEPTH False
reserve_policy single_path Reserve Policy True
size_in_mb 73400 Size in Megabytes False



DISK1 (Firmware Seagate)

U0.1-P1/Z1-A8 Other SCSI Disk Drive

Manufacturer................SEAGATE
Machine Type and Model......ST373307LC
Part Number.................4 Seagate Al
ROS Level and ID............30303033
Serial Number...............3KP1LWC5
EC Level....................l rights r
Device Specific.(Z0)........000003128B00013E
Device Specific.(Z1)........
Device Specific.(Z2)........opyr
Device Specific.(Z3)........ight
Device Specific.(Z4)........c) 2
Device Specific.(Z5)........00

# lsattr -l hdisk1 -E
clr_q no Device CLEARS its Queu.on err. True
max_transfer 0x40000 Maximum TRANSFER Size True
maxlun 31 BLOCK size True
pvid 0052a69efdee6df7(cut) Physical volume identifier False
q_err yes Use QERR bit True
q_type none Queuing TYPE True
queue_depth 1 Queue DEPTH True
reassign_to 120 REASSIGN time out value True
rw_timeout 30 READ/WRITE time out value True
start_timeout 60 START unit time out value True

gkal.USUNTO@kalasoft.com.pl wrote:
> Hajo Ehlers wrote:
> > gkal.USUNTO@kalasoft.com.pl wrote:
> >> Helo.
> >> Machine p510
> >> OSLEVEL 5.3
> >>
> > ...
> >> But Write performance for ST373307LC from Seagate
> >> is unacceptable:
> >>
> >> For ST373307LC from IBM transfer rate is ca 60 MB/sec.
> >>
> >> For ST373307LC fropm SEAGATE is ca 16 MB/sec.
> >>
> >> 1. Why?
> >
> > Please post a
> > $ lsattr -El hdiskN
> >
> > for each disk
> > hth
> > Hajo
> >
> DISK0 (Firmware IBM)
>
>
> U787E.001.AAA3763-P1-T11-L4-L0 16 Bit LVD SCSI Disk Drive (73400 MB)
>
> Manufacturer................IBM
> Machine Type and Model......ST373307LC
> FRU Number..................00P3072
> ROS Level and ID............4335304A
> Serial Number...............000869AC
> EC Level....................H12094
> Part Number.................00P2672
> Device Specific.(Z0)........000003129F00013E
> Device Specific.(Z1)........0812C512
> Device Specific.(Z2)........0002
> Device Specific.(Z3)........04245
> Device Specific.(Z4)........0001
> Device Specific.(Z5)........22
> Device Specific.(Z6)........H12094
>
> # lsattr -l hdisk0 -E
> PCM PCM/friend/scsiscsd Path Control Module False
> algorithm fail_over Algorithm True
> dist_err_pcnt 0 Dist. Error Perc. True
> dist_tw_width 50 Dist. Error Sample Time True
> hcheck_interval 0 Health Check Interval True
> hcheck_mode nonactive Health Check Mode True
> max_transfer 0x40000 Maximum TRANSFER Size True
> pvid 00c329ff702ead3c(cut) Physical volume id. False
> queue_depth 3 Queue DEPTH False
> reserve_policy single_path Reserve Policy True
> size_in_mb 73400 Size in Megabytes False
>

> U0.1-P1/Z1-A8 Other SCSI Disk Drive
....
> # lsattr -l hdisk1 -E
> clr_q no Device CLEARS its Queu.on err. True
> max_transfer 0x40000 Maximum TRANSFER Size True
> maxlun 31 BLOCK size True
> pvid 0052a69efdee6df7(cut) Physical volume identifier False
> q_err yes Use QERR bit True
> q_type none Queuing TYPE True
> queue_depth 1 Queue DEPTH True
> reassign_to 120 REASSIGN time out value True
> rw_timeout 30 READ/WRITE time out value True
> start_timeout 60 START unit time out value True

The first thing to test is to increase the queue_depth
$ chdev -l hdisk1 -a q_type=simple -a queue_depth=3

and/or read
http://www.unet.univie.ac.at/aix/aix.../scsiqueue.htm

BTW: Any attribut with an - True - can be changed.

hth
Hajo


and check the speed again.

(cut)
> $ chdev -l hdisk1 -a q_type=simple -a queue_depth=3

topas -i 1


Disk Busy% KBPS TPS KB-Read KB-Writ
hdisk2 100.0 72192.0 282.0 0.0 72192.0


It works.
Thanks a lot.

with regards
Grzegorz