Fedora Users — Re: dump runs at ~ 4 MB pr. second using Fedora Core 2 instead of the ~ 33 MB pr. second I am used to from previous distributions !

VJ wrote:

What are the settings of your hard disks? Try running hdparm to see and change. Normally using 32bit drivers and enabling DMA brings dramatic change in data transfer.

That was my first thought too, since I had a problem with the 2.4.27 kernel refusing to use dma for the backup disk for some bizarre reason.

However hdparm -c and -d reports that 32 bit data transfer and dma are being used.

VJ ----- Original Message ----- From: "Kristian Elof Sørensen" <elof@xxxxxxxx> To: <fedora-list@xxxxxxxxxx> Sent: Sunday, September 12, 2004 1:02 PM Subject: dump runs at ~ 4 MB pr. second using Fedora Core 2 instead of the ~ 33 MB pr. second I am used to from previous distributions !

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


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