Let’s try the speed test which comes with Bacula’s btape utility.
This is Bacula 7.4.0 on FreeBSD 10.2, with a Dell TL4000 LTO-4 tape library.
$ sudo mt -f /dev/sa1 /dev/sa1 status Drive: sa1: <IBM ULT3580-HH4 C7Q1> Serial Number: 1K10012996 --------------------------------- Mode Density Blocksize bpi Compression Current: 0x46:LTO-4 variable 323215 enabled (0x1) --------------------------------- Current Driver State: at rest. --------------------------------- Partition: 0 Calc File Number: 0 Calc Record Number: 0 Residual: 0 Reported File Number: 0 Reported Record Number: 0 Flags: BOP $ sudo btape -c /usr/local/etc/bacula/bacula-sd.conf /dev/nsa1 Tape block granularity is 1024 bytes. btape: butil.c:291-0 Using device: "/dev/nsa1" for writing. btape: btape.c:471-0 open device "LTO_0" (/dev/nsa1): OK *rewind btape: btape.c:576-0 Rewound "LTO_0" (/dev/nsa1) *speed btape: btape.c:1055-0 Test with zero data, should give the maximum throughput. btape: btape.c:904-0 Begin writing 3 files of 1.073 GB with raw blocks of 64512 bytes. ++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 119.3 MB/s +++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 134.2 MB/s +++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 153.4 MB/s btape: btape.c:379-0 Total Volume bytes=3.221 GB. Total Write rate = 134.2 MB/s btape: btape.c:904-0 Begin writing 3 files of 2.147 GB with raw blocks of 64512 bytes. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 165.1 MB/s +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 165.1 MB/s ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 178.9 MB/s btape: btape.c:379-0 Total Volume bytes=6.442 GB. Total Write rate = 169.5 MB/s btape: btape.c:904-0 Begin writing 3 files of 4.294 GB with raw blocks of 64512 bytes. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 178.9 MB/s +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 186.7 MB/s +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 178.9 MB/s btape: btape.c:379-0 Total Volume bytes=12.88 GB. Total Write rate = 181.4 MB/s btape: btape.c:1067-0 Test with random data, should give the minimum throughput. btape: btape.c:904-0 Begin writing 3 files of 1.073 GB with raw blocks of 64512 bytes. ++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 39.77 MB/s +++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 71.58 MB/s +++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 71.58 MB/s btape: btape.c:379-0 Total Volume bytes=3.221 GB. Total Write rate = 56.51 MB/s btape: btape.c:904-0 Begin writing 3 files of 2.147 GB with raw blocks of 64512 bytes. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 89.48 MB/s +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 89.48 MB/s ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 89.48 MB/s btape: btape.c:379-0 Total Volume bytes=6.442 GB. Total Write rate = 89.48 MB/s btape: btape.c:904-0 Begin writing 3 files of 4.294 GB with raw blocks of 64512 bytes. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 102.2 MB/s +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 95.44 MB/s +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 102.2 MB/s btape: btape.c:379-0 Total Volume bytes=12.88 GB. Total Write rate = 99.88 MB/s btape: btape.c:1081-0 Test with zero data and bacula block structure. btape: btape.c:959-0 Begin writing 3 files of 1.073 GB with blocks of 64512 bytes. +++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 76.70 MB/s +++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 97.61 MB/s +++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 97.61 MB/s btape: btape.c:379-0 Total Volume bytes=3.221 GB. Total Write rate = 89.48 MB/s btape: btape.c:959-0 Begin writing 3 files of 2.147 GB with blocks of 64512 bytes. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 107.3 MB/s +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 102.2 MB/s ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 107.3 MB/s btape: btape.c:379-0 Total Volume bytes=6.442 GB. Total Write rate = 105.6 MB/s btape: btape.c:959-0 Begin writing 3 files of 4.294 GB with blocks of 64512 bytes. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 113.0 MB/s +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 113.0 MB/s ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 113.0 MB/s btape: btape.c:379-0 Total Volume bytes=12.88 GB. Total Write rate = 113.0 MB/s btape: btape.c:1093-0 Test with random data, should give the minimum throughput. btape: btape.c:959-0 Begin writing 3 files of 1.073 GB with blocks of 64512 bytes. +++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 27.53 MB/s +++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 51.13 MB/s +++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=1.073 GB. Write rate = 48.80 MB/s btape: btape.c:379-0 Total Volume bytes=3.221 GB. Total Write rate = 39.28 MB/s btape: btape.c:959-0 Begin writing 3 files of 2.147 GB with blocks of 64512 bytes. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 58.04 MB/s +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 59.65 MB/s ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=2.147 GB. Write rate = 58.04 MB/s btape: btape.c:379-0 Total Volume bytes=6.442 GB. Total Write rate = 58.56 MB/s btape: btape.c:959-0 Begin writing 3 files of 4.294 GB with blocks of 64512 bytes. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 64.10 MB/s +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 61.35 MB/s ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ btape: btape.c:606-0 Wrote 1 EOF to "LTO_0" (/dev/nsa1) btape: btape.c:405-0 Volume bytes=4.295 GB. Write rate = 64.10 MB/s btape: btape.c:379-0 Total Volume bytes=12.88 GB. Total Write rate = 63.16 MB/s *
