Les Mikesell wrote:
> Evren Yurtesen wrote:
>
>>> If your filesystem isn't a good place to store files, there is not
>>> much an application can do about it. Perhaps it would help if you
>>> mentioned what kind of scale you are attempting with what server
>>> hardware. I know there are some people on the list handling what I
>>> would consider large backups with backuppc. If yours is
>>> substantially smaller perhaps they can help diagnose the problem.
>>> Maybe you are short on RAM and swapping memory to disk with large
>>> rsync targets.
>>
>> I know that the bottleneck is the disk. I am using a single ide disk
>> to take the backups, only 4 machines and 2 backups running at a
>> time(if I am not remembering wrong).
>
> That's still not very informative. Approximately how much data do those
> targets hold (number of files and total space used)? Are you using tar
> or rsync? If you are running Linux, what does 'hdparm -t -T' say about
> your disk speed (the smaller number)? And what filesystem are you using?
There are 4 hosts that have been backed up, for a total of:
* 16 full backups of total size 72.16GB (prior to pooling and
compression),
* 24 incr backups of total size 13.45GB (prior to pooling and
compression).
Host User #Full Full Age (days) Full Size (GB)
Speed
(MB/s) #Incr Incr Age (days) Last Backup (days)
State
Last attempt
host1 4 5.4 3.88 0.22 6 0.4 0.4
idle idle
host2 4 5.4 2.10 0.06 6 0.4 0.4
idle idle
host3 4 5.4 7.57 0.14 6 0.4 0.4
idle idle
host4 4 5.4 5.56 0.10 6 0.4 0.4 idle
idle
# Pool is 17.08GB comprising 760528 files and 4369 directories (as of
3/27 05:54),
# Pool hashing gives 38 repeated files with longest chain 6,
# Nightly cleanup removed 10725 files of size 0.40GB (around 3/27 05:54),
# Pool file system was recently at 10% (3/27 07:16), today's max is 10%
(3/27 01:00) and yesterday's max was 10%.
>> I see that it is possible to use raid to solve this problem to some
>> extent but the real solution is to change backuppc in such way that it
>> wont use so much disk operations.
>
> First we should find out if your system is performing badly compared to
> others or if you are just expecting too much. As an example, one of my
> systems is backing up 20 machines and the summary says:
> Pool is 152.54GB comprising 2552606 files and 4369 directories
> This is a RAID1 (mirrored, so no faster than a single drive) on IDE
> drives and the backups always complete overnight.
>
>>>> I wonder what is the mechanical stress this poses on the hard drive
>>>> when it has to work 24/7 moving it's head like crazy.
>>> They'll die at some random time averaging around 4-5 years - just
>>> like any other hard drive. Disk heads are made to move...
>>
>> Perhaps, but there is a difference if they are moving 10 times or
>> 100000 times. Where the difference is that the possibility of failure
>> due to mechanical problems increases 10000 times.
>
> No, it doesn't make a lot of difference as long as the drive doesn't
> overheat. The head only moves so fast and it doesn't matter if it does
> it continuously. However, if your system has sufficient RAM, it will
> cache and optimize many of the things that might otherwise need an
> additional seek and access.
>
I cant see how you can reach to this conclusion. So you say that a car
which was driven 10miles have the same possibility of breaking down
compared to the same model car driven for 100000miles? There are
frictions involved when head moves in the hard drive.
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