Re: [BackupPC-users] very slow backup on windows

On 17/09/14 19:18, Nicola Scattolin wrote:
> Hi,
> i have backuppc backing up a couple of linux machines of 30/40 GB each 
> and a windows shared folder of 1.1 TB.
> Usually it takes one day and a half to backup the windows folder with a 
> speed around 7 mbit/s but now the speed has decreased to 5 and it takes 
> up ot 3 days to make full backup.
> I have already tried to reboot the server but speed remain the same.
> so some details, the backup server is proxmox virtualized, 2.5 Gb of ram 
> and 2 processors (seems enaught since never reach more than 80% when 
> making backup) 10/100 eth integrated port.
> The windows system is a windows server 2003, also proxmox virtualized, 1 
> processor.
> Backup is make on local environment, at night so lan traffic is very low 
> or null.
> host configuration on backuppc is:
> XderMethod:smb
> ClientCharsetLegacy:iso-8859-1
> SmbClientFullCmd: $smbClientPath \\$host\$shareName $I_option -U 
> $userName -E -d 1 -c tarmode\ full -Tc$X_option - $fileList
> SmbClientIncrCmd: $smbClientPath \\$host\$shareName $I_option -U 
> $userName -E -d 1 -c tarmode\ full -TcN$X_option $timeStampFile - $fileList
> compresslevel:3 (maybe i can reduce compression to save time, IF the 
> problem is backuppc server speed)
>
> how can i speed up my backups? also on linux machine max speed is 11 
> mbit/s, so not so much.
> thank yuo

Whenever you have a performance issue such as this, there is almost one
of a few problems:
1) Not enough CPU to perform the task (regardless of the number of
CPU's, some tasks will only use a single CPU
2) Not enough disk I/O
3) Not enough bandwidth/latency
4) Not enough RAM

In this case, items 1, 2 and 4 relate to both the machine being backed
up as well as the backuppc server.

If the problem is CPU on the backuppc server, then disable compression
and it will help.
If the problem is CPU on the client, then you will need to find a way to
fix that by adding additional CPU's or faster CPU's, or changing the
backup method.

If the problem is disk I/O (which I suspect is very likely, especially
if both the client and backuppc server are VM's on the same physical
disk/array. The answer here is to either move the backup server to a
distinct physical machine, or add additional spindles, or increase the
performance of the existing spindles (move to faster disks/SSD), or move
to a different RAID level (if you are using RAID1/5/6 move to RAID10).
Or you could have some other underlying major performance issue here.

If the problem is lack of RAM on either backuppc server or the client,
then you will need to increase that to reduce the swap space usage,
which will help solve problem 2.

Finally, if it is bandwidth/latency between the hosts (100Mb/s is only
10MB/s, or theoretical maximum performance of 35GB/hour) upgrade to
1Gbps, or even 10Gbps, or consider using a different backup method which
doesn't involve copying unchanged files over the limited bandwidth (eg,
rsync or rsyncd, but this will increase CPU and/or RAM load).

Like any performance issue, you will need to measure different parts of
the system to find out which part is under the most pressure/stress.
Then you can work out how best to resolve this issue.

Regards,
Adam

-- 
Adam Goryachev
Website Managers
www.websitemanagers.com.au


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