On Tuesday 04 September 2012 12:44:26 Götz Reinicke wrote:
Hi Tony,
because I suggest just something very general I post off list :)
From my POV as I'm currently facing similar setups with different hardware rolling back from fine granular setups to simple 'bigger' less complex configurations. (we do have 6 iscsi storages from 2TB (sun ZFS) up to 32 TB)
keep it small and simple! :)
I think you are very familiar with the general problems of big HW raids and big filesystems like rebuild or check times, but splitting up and adding more complex layers like multiple raids joining in lvm etc. makes debugging and general handling very hard.
On the other hand, I checked and read a lot about filesystems the last days being faced with serving user windows samba profiles with lot of small files and big video/audio data etc.
Long story short:
I usually do one raidvolume per hardware raid box; e.g. we use 16*1TB drives. Raid6 or Raid5 with spare. I did not notice big performance differences.
I use LVM to make partitions or I prefer using just one big partition.
I tried xfs and ext4 and will go with ext4 as some test went better for my setup and from what I read it looks not bad :)
I think you can combine block level devices (like multiple raid boxes) by LVM into one bigger LV.
And last but not least: The CPU/RAM/Network of the host serving the files is also very important! :)
I noticed, that the same iscsi storage got about 70MB/s on a new server (xeon multicore), while on the old fileserver it just got up to 40MB/s.
my2cents :) regards . Götz
May be worth reading:
http://www.techforce.com.br/news/linux_blog/lvm_raid_xfs_ext3_tunin g_for_small_files_parallel_i_o_on_debian#.UEPSI1RqYso
http://monolight.cc/2011/02/linux-filesystems-small-file-performanc e-on-hdds/
http://unix.stackexchange.com/questions/28756/what-is-the-most-high -performance-linux-filesystem-for-storing-a-lot-of-small-fi
https://wiki.archlinux.org/index.php/Ext3
https://wiki.archlinux.org/index.php/Ext4#Tips_and_tricks
Am 04.09.12 13:10, schrieb Tony Molloy:
Hi,
I've just got possession of a Dell PE R720 with 2 MD1200 disk enclosures.
Both MD1200 are fully populated with 12 x 3 TB disks
The system will basically be a student file-server running CentOS 6.x serving various size files from small c programs to multi gigabyte audio and video files over GB ethernet.
The first MD1200 will be configured as the NFS disk. The requirements are for 6 fixed equally sized partitions, one for each cohort of students. For this I was thinking of splitting the MD1200 into 2 RAID5 arrays with a hot spare each. Then partitioning each into 3 ext4 partitions.
The second MD1200 will be used to backup the first, using BackupPC and for other storage purposes.
As I won't know the storage requirements for the "backup partition" and they will probably change over time anyway. I was thinking of using LVM for it. So how to partition the MD1200 for LVM. I don't want to put all 12 disks in a RAID5 and put a LVM volume on it. Can I split it into 2 RAID5 and have a LVM volume spanning both.
Any suggestions.
Just remember I'm due to retire at the end of this month so this will be my last big job for the Dept. And due to financial constraints I will not be replaced. So I will be handing this machine over to a co- worker who is basically a Windoze admin with only a basic knowledge of Linux so nothing too fancy. ;-)
Thanks,
Tony
--
Tony Molloy
CTO, Dept. of Comp. Sci. University of Limerick Limerick. Ireland _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos