Using the Tape Speed Test Utility
Posted by Sven Koester on 08 January 2010 14:03
As of 3.2.2, PresSTORE includes a simple tape drive speed test utility. This utility can be used to check the data transfer to and from a single tape drive.
The utility is exposed over the CLI interface like:
cli::tests::tape::readwrite drivename datasize [blocksize]
The commands read/write data from/to the given PresSTORE drivename with the given datasize using the optional blocksize. (default = 32 kB).
Both sizes also accept the following optional modifiers:
k|K = kilo (= size * 1024)The command reports the write speed and the read speed, both in KBytes/sec.
m|M = mega (= size * 1024 * 1024)
g|G = giga (= size * 1024 * 1024 * 1024)
For details calling commands via the CLI please consult the CLI guide.
# cd /usr/local/aw
# bin/nsdchat -c cli::tests::tape::readwrite Drive1 1g
# bin/nsdchat -c cli::tests::tape::readwrite Drive1 1g 64k
# bin/nsdchat -c cli::tests::tape::readwrite Drive1 1g 128k
The first command uses the default blocksize of 32 kB. Here (LTO3 device connected via Fibre Channel) the speed does not vary much with the blocksize, the results may differ when using other connection technologies, like SAS (Serial attached SCSI) for example.
Not all blocksizes are supported, depending on the hardware. Namely on older SCSI devices, blocksizes above 32 KByte may be unsupported.
After performing the speed tests, the tape must be re-labeled in PresSTORE in order to be used again.