[ILUG] Dump very slow across gigabit network

[Conor Daly]

On Fri, Sep 14, 2007 at 11:50:02AM +0100 or so it is rumoured hereabouts, 
Conor Daly thought:
> 
> Going to try a cpio test next...

So, I tried various permutations of dump, cpio, tar, dd and scp.  Commands
are:

scp /path/to/7Gb/file ka2:

dump -0f ka2:/path/to/file /filesystem

tar cf - /path | ssh ka2 'dd of=/path/to/file'
tar cf - /path | ssh ka2 'dd of=/dev/nst0'

tar cf /path/to/tarball 
cat /path/to/tarball | ssh ka2 'dd of=/path/to/file'


The results come out like this:

Method:                            speed (MB/s) ratio
scp local file to remote disk:     40           1
dump to local disk:                 7.5         0.19
dump to remote disk:                1.5         0.04
dump to remote tape:                1.5         0.04
dump remote disk to remote disk:   33.5         0.84
dump remote disk to remote tape:   16           0.4
cp local file local disk:          49           1.22
cp remote file to remote disk:     14.3         0.36
cpio to local disk:                43           1.08
cpio to remote disk:                0.03        0.0009
tar and dd to remote disk:         17           0.43
cat tarball and dd to remote disk: 34           0.85
tar and dd to remote tape:          7           0.18
cat tarball and dd to remote tape:  8.5         0.21

local is the client machine that I want to backup.  Remote is the machine
that hosts the tape drive.  anything listed as remote to remote happens
entirely on the remote machine with no network involvement.  Anything
listed as local to local happens on the local machine with no network
involvement.  local to remote goes across a gigabit network via crossover
cable (no switches or other hosts involved).

Conor

-- 
Conor Daly <conor.daly at cod.homelinux.org>
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