Rsync taking up all Ram, 800MB!

[humbletech99]

I'm trying to rsync between two servers like so

rsync -av -e ssh /path/to/dir1 root@machine2:/path/to/dir2
building file list ... done
file1
file2
file3
...

There are a huge lot of files in dir1 that I am trying to sync over to dir2 on the other machine, which holds a copy of nearly all of these files, perhaps 1 or 2 days out of day, so the changeset shouldn't be everything.

The problem is that rsync is taking up all the Ram, nearly 800MB out of a 1Gb machine on the source machine and the same on the destination machine (and that's only because the other processes on the servers are taking up the rest). Here is the line from top:

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND                                                                                                                 
30802 root      16   0  759m 609m  736 S  0.0 60.3   2:29.90 rsync

Is this behaviour normal? Is this a bug and is there a way to work around it? I am using rsync version 2.6.9 protocol version 29 on the first server and rsync version 2.6.8 protocol version 29 on the second.

[bigtomrodney]

Unix systems will always try to use approximately 90% of your RAM. It's simply making the best use of the RAM, no poin in leaving it empty! If rsyc is moving a lot of files it could benefit from the cache space so it is being assigned it. I would say if you started another few applications the memory will be spread out accordingly. It shouldn't affect the performance of other applications.

[humbletech99]

I know about the cache thing, but rsync itself is taking up 800MB, not cached.

Perhaps it's hitting a file that is large, but I thought that rsync works on timestamps, so it should just compare and recopy but still not use up 800MB!

The cache went down to practically nothing, which is not the norm from my observations.