LTO4 Slow, Is my block size configuration being read?

[dcollings]

I am using a Tandberg Data 1x7 Magnum LTO4 Autoloader. When I use gnutar with a block size of 2048 (tar -b 4096) I can back up a 2.6 gig iso file in 37 seconds. When I use amanda, the same file takes 4 minutes. I used the following configure line when I compiled my amanda installation.

/downloads/amandasource/amanda-2.6.0p1/configure --with-maxtapeblocksize=2048 --with-user=amandabackup --with-group=disk --with-configdir=/etc/amanda

I then added the blocksize line to my amanda.conf

define tapetype LTO4 {
comment "LTO4 Library"
length 802816 mbytes
blocksize 2048 kbytes
filemark 0 kbytes

It still takes 4 minutes.

How do I know if the maxtapeblocksize parameter is active. Is there a log file that will tell me what block size the job was backed up with?

[nhwhite212]

I am having exactly the same problem. Rebuilt amanda with a block size of 512, specified it in tapetype, yet the log file says it is still 32k. Very annoying, can't go into production until I fix problem. I have run amanda for years on a solaris system (same tape, LTO2 drive) with 32k blocks and it would drive it at around 20MB/sec
Now I get 2MB.

[dustin]

Note that the logfile lies about its blocksize. It always says 32k. This has been fixed in trunk, but is not in the latest release.

nhwhite212: I assume you meant 512k? Amanda's minimum block size is 32k.

Try setting
device_property "BLOCK_SIZE" "2 mbytes"
in the top-level of amanda.conf.