I have the following in my dump type:

tape_splitsize 40 Gb
split_diskbuffer "/dumps/amanda/split_diskbuffer"

While running amdump for a 2TB filesystem, it is observed, with iostat, that AMANDA is simultaneously reading and writing the filesystem where split_diskbuffer is located.

On our system, /dumps/amanda/split_diskbuffer is a dedicated disk (a logical volume on dedicated drives in a HP array). There are no other logical volumes on the same spindle.

What can be done to ensure that AMANDA uses the disks in a more sensible way?

Do I need to have 40GB of RAM and buffer the split filesystem in RAM?

I can get 80MByte/sec over the network. The 2TB array is on a Solaris 10 machine with a massive RAID array. Yet my backups are struggling along at just 20Mbyte/sec or less.

avg-cpu: %user %nice %system %iowait %steal %idle
0.50 0.00 7.96 25.62 0.00 65.92

Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn
cciss/c0d0 0.00 0.00 0.00 0 0
cciss/c0d1 576.24 18712.87 32938.61 18900 33268
dm-0 0.00 0.00 0.00 0 0
dm-1 0.00 0.00 0.00 0 0
dm-2 0.00 0.00 0.00 0 0
dm-3 0.00 0.00 0.00 0 0
dm-4 8465.35 18712.87 32435.64 18900 32760