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Using S.M.A.R.T. Disk Monitor 197

Discovered SEAGATE ST373307LC S/N "3HZ03822" on /dev/sg2 (SMART enabled)(70007 MB)

Sending command: -B S,08,12,10,00,FF,FF,00,00,FF,FF,FF,FF,00,20,00,00,00,00,00,00

Result: (SUCCESS) - The write cache was already disabled.

Program Ended.

Finally, a warning .. the write cache is typically disabled for a reason. When the cache is disabled, the disk does not

return a complete code to the host until the disk has physically recorded the block(s). When write cache is enabled,

the disk immediately responds to the host telling it the I/O has been completed. This can significantly improve write

performance.

You have a risk in that when you use a write cache, a power loss will result in permanent data loss of any writes that

have occurred between the time the disk last flushed the pending writes to the disk drive and the power failure. The

amount of time it takes between flushing is typically a few seconds, but this value is vendor/product/device specific.

You may also use the mode page editor to control the write cache. The -wce was introduced because enabling /

disabling the write cache is a common activity performed by system administrators.

1.51 Write Protected Media Test

This feature was added in release 1.28. It provides a convenient test to see if the media in a device (typically a tape

drive) is write protected.

Note, some operating systems, such as HP/UX do not support querying tape drives unless there is media inserted

into them.

Syntax

-wp {devicefile}.

Example:

# ./smartmon-ux -wp

http://www.SANtools.com

Discovered MITSUMI CD-ROM FX4830T!B S/N " " on /dev/rdsk/c0t0d0 (CD/DVD)

Discovered IBM DDRS-39130LC S/N "RE371797" on /dev/rdsk/c2t5d0 (SMART enabled)(8678 MB)

Discovered IBM DDRS-39130LC S/N "RE371728" on /dev/rdsk/c2t6d0 (SMART enabled)(8678 MB)

Discovered HP C1533A S/N " " on /dev/rmt/0mn (Media WRITE-PROTECTED)

Program Ended.

The test above was run without any device options on a HP/UX machine. It scanned for all devices and reported that

the C1533A tape had write-protected media. The test below was run on the same machine, but we used wild-cards

for various device names that are associated with that tape.

# ./smartmon-ux -wp /dev/rmt/0m*

http://www.SANtools.com

********************************************************************

* F o r U N I S Y S A U C K L A N D E v a l u a t i o n *

* This software will expire on *

* 05/05/05 (22 days remaining). *

********************************************************************

Discovered HP C1533A S/N " " on /dev/rmt/0m (Media WRITE-PROTECTED)

Discovered HP C1533A S/N " " on /dev/rmt/0mb (Media WRITE-PROTECTED)

Discovered HP C1533A S/N " " on /dev/rmt/0mn (Media WRITE-PROTECTED)

Discovered HP C1533A S/N " " on /dev/rmt/0mnb (Media WRITE-PROTECTED)

Program Ended.

We then slid over the write protect tab ...

# ./smartmon-ux -wp /dev/rmt/0*

http://www.SANtools.com

********************************************************************