unix command to check for hardware compression

[Carmela Agustin]

i have a tandberg sdlt220 autoloader connected directly to my hp itanium server. how can i check if the autoloader's hardware compression is turned on? what unix command can i use? thanks!

[RAC_1 · Accepted solution]

There are two ways to compress the data.
1. With backup software. You compress the data and put it on tape.

2. Use device capable of doing compression.
Check the device files.
Run lssf on device files and use the one that says best density. When you start backing up data, it should show compression light glowing on the tape drive.

lssf /dev/rmt/*

[Matthew_50]

you can try attach 'tapeinfo' utility.

Typical output from the command for LTO

For an Ultrium device:

Manufacturer = HP
Product Id = Ultrium 1-SCSI
Product Revision Level = N16D

Data Retrieved from Drive Capacity Logs (MBytes)
Max Capacity Main Partition = 100224
Rem Capacity Main Partition = 100216
Max Capacity Alt Partition = 0
Rem Capacity Alt Partition = 0

Data Retrieved from Drive Compression Logs
Bytes to DC = 11555076
Bytes from DC = 13561348
Bytes to Tape = 6033760
Bytes from Tape = 6788536
Compression ratio (Read) = 2.00 : 1
Compression ratio (Write) = 1.92 : 1

[Carmela Agustin]

hi RAC,

I checked using lssf and it is set to best density already:

# lssf /dev/rmt/4m
stape card instance 2 SCSI target 9 SCSI LUN 0 at&t best density available at ad
dress 0/1/1/0/1/0.9.0 /dev/rmt/4m

Hi Matthew,

I tried executing tapeinfo utility but I got this:

# tapeinfo /dev/rmt/4m

*-----------------------------------------------------*
* This command may take up to several minutes to run. *
* No other tools or processes can be running on the *
* device while this tool is running. Exit out of any *
* STM tool which maybe currently running on this *
* device before continuing. *
*-----------------------------------------------------*

Do you wish to continue? (y/n) y

There is not a license currently installed.
Do you wish to install a HP-Only support license? (y/n) y

Enter the HP-Only support license password:
Installing support license ...

*-----------------------------------------------------*
* Not able to install license password. *
*-----------------------------------------------------*

Pls help, thanks.

[Bill Hassell]

tapeinfo has the unfortunate feature of duplicating a completely different program which is part of the diagnostics package. The 'wrong' tapeinfo is in /usr/sbin and you can see the one you are running using the type command as in:

type tapeinfo

(never use which or whereis for locating a command)

If you downloaded the utility to let's say /tmp, then use the full pathname to get the right program:

/tmp/tapeinfo

The way to tell which program you are running is the startup message with no parameters in the command line, like this:

worng one:
/usr/sbin/tapeinfo

Usage: tapeinfo hardware_path

Correct one:
/tmp/tapeinfo

usage: tapeinfo [-c] [-q] -f tape_device