Enable write cache on scsi disc drive

I've got four FUJITSU MAP3735NC 73 GB SCSI disc drives connected to an
LSI LOGIC 20320-R U320 scsi controller.

I want to enable the write cache on two of the discs.

How can I do that unter SuSE Linux 9.1, kernel 2.6.5-7.104-smp?

I found no posibility to enable the discs' cache in the bios of the
controller.

Thanks,
Christian


+++++++++++++ boot.msg ++++++++++++++++

5SCSI subsystem initialized
6Fusion MPT base driver 3.01.03
6Copyright (c) 1999-2004 LSI Logic Corporation
6mptbase: Initiating ioc0 bringup
6ioc0: 53C1030: Capabilities={Initiator} 6Fusion MPT SCSI Host driver
3.01.03 6scsi0 : ioc0: LSI53C1030, FwRev=01032700h, Ports=1, MaxQ=222,
IRQ=26
5 Vendor: LSILOGIC Model: 1030 IM Rev: 1000
5 Type: Direct-Access ANSI SCSI revision: 02
5SCSI device sda: 71553024 512-byte hdwr sectors (36635 MB) 5SCSI device
sda: drive cache: write through 6 sda: sda1 sda2 sda3 5Attached scsi
disk sda at scsi0, channel 0, id 0, lun 0
5 Vendor: FUJITSU Model: MAP3735NC Rev: 0108
5 Type: Direct-Access ANSI SCSI revision: 03
5SCSI device sdb: 143571316 512-byte hdwr sectors (73509 MB) 5SCSI
device sdb: drive cache: write through 6 sdb: sdb1 5Attached scsi disk
sdb at scsi0, channel 0, id 2, lun 0
5 Vendor: FUJITSU Model: MAP3735NC Rev: 0108
5 Type: Direct-Access ANSI SCSI revision: 03
5SCSI device sdc: 143571316 512-byte hdwr sectors (73509 MB) 5SCSI
device sdc: drive cache: write through 6 sdc: sdc1 5Attached scsi disk
sdc at scsi0, channel 0, id 3, lun 0
5 Vendor: FUJITSU Model: MAP3735NC Rev: 0108
5 Type: Direct-Access ANSI SCSI revision: 03
5SCSI device sdd: 143571316 512-byte hdwr sectors (73509 MB) 5SCSI
device sdd: drive cache: write back 6 sdd: sdd1 5Attached scsi disk sdd
at scsi0, channel 0, id 4, lun 0
5 Vendor: FUJITSU Model: MAP3735NC Rev: 0108
5 Type: Direct-Access ANSI SCSI revision: 03
5SCSI device sde: 143571316 512-byte hdwr sectors (73509 MB) 5SCSI
device sde: drive cache: write back 6 sde: sde1 5Attached scsi disk sde
at scsi0, channel 0, id 5, lun 0

Previously Christian Marx wrote:
I've got four FUJITSU MAP3735NC 73 GB SCSI disc drives connected to an
LSI LOGIC 20320-R U320 scsi controller.

I want to enable the write cache on two of the discs.

How can I do that unter SuSE Linux 9.1, kernel 2.6.5-7.104-smp?

I found no posibility to enable the discs' cache in the bios of the
controller.

Try scsi-config. In the sub-menu "Cache Control Page" there
is a button "Write cache enabled", that should do it. Also
note the big, red warning not to turn on write cache, unless
you know what you are doing. You might also want to read the
relevant section of the man-page. Don't forget to save the info
on the device, or it will be gone after the next reset. (Again
see man-page for details.)

Theoretically you can do all this also with "scsiinfo" on the
commandline, but the man-page of scsiinfo says "experts only" and
to use scsi-config instead.

In Debian scsi-config is in package "scsitools". I have no idea
were SuSE stores it.

Regards,
Arno



Thanks,
Christian


+++++++++++++ boot.msg ++++++++++++++++

5SCSI subsystem initialized
6Fusion MPT base driver 3.01.03
6Copyright (c) 1999-2004 LSI Logic Corporation
6mptbase: Initiating ioc0 bringup
6ioc0: 53C1030: Capabilities={Initiator} 6Fusion MPT SCSI Host driver
3.01.03 6scsi0 : ioc0: LSI53C1030, FwRev=01032700h, Ports=1, MaxQ=222,
IRQ=26
5 Vendor: LSILOGIC Model: 1030 IM Rev: 1000
5 Type: Direct-Access ANSI SCSI revision: 02
5SCSI device sda: 71553024 512-byte hdwr sectors (36635 MB) 5SCSI device
sda: drive cache: write through 6 sda: sda1 sda2 sda3 5Attached scsi
disk sda at scsi0, channel 0, id 0, lun 0
5 Vendor: FUJITSU Model: MAP3735NC Rev: 0108
5 Type: Direct-Access ANSI SCSI revision: 03
5SCSI device sdb: 143571316 512-byte hdwr sectors (73509 MB) 5SCSI
device sdb: drive cache: write through 6 sdb: sdb1 5Attached scsi disk
sdb at scsi0, channel 0, id 2, lun 0
5 Vendor: FUJITSU Model: MAP3735NC Rev: 0108
5 Type: Direct-Access ANSI SCSI revision: 03
5SCSI device sdc: 143571316 512-byte hdwr sectors (73509 MB) 5SCSI
device sdc: drive cache: write through 6 sdc: sdc1 5Attached scsi disk
sdc at scsi0, channel 0, id 3, lun 0
5 Vendor: FUJITSU Model: MAP3735NC Rev: 0108
5 Type: Direct-Access ANSI SCSI revision: 03
5SCSI device sdd: 143571316 512-byte hdwr sectors (73509 MB) 5SCSI
device sdd: drive cache: write back 6 sdd: sdd1 5Attached scsi disk sdd
at scsi0, channel 0, id 4, lun 0
5 Vendor: FUJITSU Model: MAP3735NC Rev: 0108
5 Type: Direct-Access ANSI SCSI revision: 03
5SCSI device sde: 143571316 512-byte hdwr sectors (73509 MB) 5SCSI
device sde: drive cache: write back 6 sde: sde1 5Attached scsi disk sde
at scsi0, channel 0, id 5, lun 0

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Arno Wagner wrote:
Previously Christian Marx wrote:

I've got four FUJITSU MAP3735NC 73 GB SCSI disc drives connected to an
LSI LOGIC 20320-R U320 scsi controller.


I want to enable the write cache on two of the discs.


How can I do that unter SuSE Linux 9.1, kernel 2.6.5-7.104-smp?


I found no posibility to enable the discs' cache in the bios of the
controller.


Try scsi-config. In the sub-menu "Cache Control Page" there
is a button "Write cache enabled", that should do it. Also
note the big, red warning not to turn on write cache, unless
you know what you are doing. You might also want to read the
relevant section of the man-page. Don't forget to save the info
on the device, or it will be gone after the next reset. (Again
see man-page for details.)

Theoretically you can do all this also with "scsiinfo" on the
commandline, but the man-page of scsiinfo says "experts only" and
to use scsi-config instead.

In Debian scsi-config is in package "scsitools". I have no idea
were SuSE stores it.


Well thanks for the detailed information. I found scsi-config in the
xscsi package. I didn't know that write caching is such a sensitive
topic when it comes to scsi disks, so I decided to disable it since I
run a software raid-5 on top of those disks.

Regards,
Christian