Re: Performance problems with millions of inodes

Christoph Litauer
2008-06-25T14:45:44Z

Christoph Litauer schrieb:
> Hi,
>
> sorry if this has been asked before, I am new to this mailing list. I
> didn't find any hints in the FAQ or by googling ...
>
> I have a backup server driving two kinds of backup software: bacula and
> backuppc. bacula saves it's backups on raid1, backuppc on raid2
> (different hardware, but both fast hardware raids).
> I have massive performance problems with backuppc which I tracked down
> to performance problems of the filesystem on raid2 (I think so). The
> main difference between the two backup systems is that backuppc uses
> millions of inodes for it's backup (in fact it duplicates the directory
> structure of the backup client).
>
> raid1 consists of 91675 inodes, raid2 of 143646439. The filesystems were
> created without any options. raid1 is about 7 TB, raid2 about 10TB. Both
> filesystems are mounted with options
> '(rw,noatime,nodiratime,ihashsize=65536)'.
>
> I used bonnie++ to benchmark both filesystems. Here are the results of
> 'bonnie++ -u root -f -n 10:0:0:1000':
>
> raid1:
> -------------------
> Sequential Output: 82505 K/sec
> Sequential Input : 102192 K/sec
> Sequential file creation: 7184/sec
> Random file creation : 17277/sec
>
> raid2:
> -------------------
> Sequential Output: 124802 K/sec
> Sequential Input : 109158 K/sec
> Sequential file creation: 123/sec
> Random file creation : 138/sec
>
> As you can see, raid2's throughput is higher than raid1's. But the file
> creation times are rather slow ...
>
> Maybe the 143 million inodes cause this effect? Any idea how to avoid it?
>

Just another (xfs_)info about raid2:

meta-data=/dev/backuppc/backuppc isize=256 agcount=32,
agsize=79691776 blks
= sectsz=512 attr=0
data = bsize=4096 blocks=2550136832, imaxpct=25
= sunit=0 swidth=0 blks, unwritten=1
naming =version 2 bsize=4096
log =internal bsize=4096 blocks=32768, version=1
= sectsz=512 sunit=0 blks, lazy-count=0
realtime =none extsz=4096 blocks=0, rtextents=0