Problem:
dump of an entire partition on one disk to a file on an EIDE disk on another controller progresses at the slooow speed of approx. 4 MB pr. second
Using the same kernel on the same machine but with a heavily upgraded Redhat 7.3 instead of Fedora Core 2, dump progressed at a rate of 16-33,6 MB pr. second depending on which disk was being dumped. Write speed to the disk being written to is limited to 33,6 due to long EIDE cables.
Details:
During dump with Fedora Core 2 the system load is between 2,2 and 3,2, the three dump threads are consuming 1-3% cpu and less than 2 MB of memory.
During dump with Fedora Core 2 free reports that "buffers" is around 0,75 GB and "cached" around 0,65 GB during dump. Se below for snapshots.
System: Fedora Core 2 2.6.8.1 kernel compiled for SMP Dual Athlon 1,5 GB RAM 1,5 GB swap space
free:
before starting dump
bash-2.05b# free total used free shared buffers cached Mem: 1555436 129140 1426296 0 4460 26456 -/+ buffers/cache: 98224 1457212 Swap: 1509352 92368 1416984
while dump is running (the numbers stays pretty much the same for the entire run of dump)
bash-2.05b# free total used free shared buffers cached Mem: 1555436 1547356 8080 0 735380 629692 -/+ buffers/cache: 182284 1373152 Swap: 1509352 120756 1388596