Les Mikesell wrote:
> On Sun, 2006-11-26 at 19:48, Adam Goryachev wrote:
>   
>> I've recently installed backuppc on my backup server, and slowly started 
>> to try and backup various machines. I started with my windows laptop via 
>> rsyncd, and recently added a couple of linux servers via rsync over ssh.
>>
>> I've had a lot of problems attempting to backup the windows machine, and 
>> sort of decided that it might just be a windows related problem, and 
>> asked a few questions on this list for help (and not had a reply yet).
>>
>> Anyway, while trying to debug why it was also having problems backing up 
>> a linux server, I noticed that the backup processes where using a LOT of 
>> memory (RAM), and that they seemed to be dying due to insufficient memory.
>> Out of Memory: Killed process 7339 (BackupPC_dump).
>>
>> So, I am now wandering how to calculate the memory requirements of 
>> backuppc. The machine I am using only has 128MB RAM, but I assume that 
>> we don't need enough memory to hold the contents of the largest file, or 
>> else most people wouldn't be able to backup large files (ie, 2GB or more)...
>>
>> Is it based on the number of files needing to be backup up, or some 
>> combination? perhaps a certain amount of memory for each 'block' of the 
>> file that is being transferred?
>>     
>
> Rsync transfers the entire directory tree to the remote with a
> certain amount of overhead taken in RAM for each file.  I'm not
> sure about the exact size, but you can work around the problem
> by breaking large runs up into separate filesystems or
> subdirectories, or switching to tar or smb methods.
>   
I don't think it is the rsync memory overheads, as it actually starts 
the backup, and gets a certain way through before it dies with the 
memory problem.

Since posting, I've found some more possibly interesting info...
I've setup the swap space (before I was running with no swap at all) and 
swap space usage peaked at around 94MB, which means to complete the 
incremental backup, I would have needed approx 220 MB RAM (with no swap 
space). I've also noticed that doing an incremental backup via the web 
interface seems to need significantly less memory, since it peaked at 
only 61MB swap space used.

When I ran it from the cmd line, I used -v, so perhaps that adds 
additional memory requirements?

Anyway, with the swap space configured, it looks like it is working ok 
for this machine. If it will work properly for my windows machine as 
well, then even better... If all goes well, then I'll get a new server 
with more RAM and more disk space to do things properly... It is just 
nice to be aware that there are fairly significant memory requirements 
for a backup server... (I assumed that a backup server would be similar 
to a file server, where memory requirements are minimal).

Regards,
Adam

-- 
Adam Goryachev
Website Managers
Ph: +61 2 8304 0000                            [EMAIL PROTECTED]
Fax: +61 2 8304 0001                            www.websitemanagers.com.au


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