On Jan 11, 2009, at 1:06 PM, Stewart Williams lists@pinkyboots.co.uk wrote:
Ross Walker wrote:
On Jan 11, 2009, at 10:13 AM, Stewart Williams lists@pinkyboots.co.uk wrote:
William Warren wrote:
Stewart Williams wrote:
I have just purchased an HP ProLiant HP ML110 G5 server and install ed CentOS 5.2 x86_64 on it.
It has the following spec:
Intel(R) Xeon(R) CPU 3065 @ 2.33GHz 4GB ECC memory 4 x 250GB SATA hard disks running at 1.5GB/s
Onboard RAID controller is enabled but at the moment I have used mdadm to configure the array.
RAID bus controller: Intel Corporation 82801 SATA RAID Controller
For a simple striped array I ran:
# mdadm --create /dev/md0 --level=0 --raid-devices=2 /dev/sdb1 / dev/sdc1 # mke2fs -j /dev/md0 # mount -t ext3 /dev/md0 /mnt
Attached are the results of 2 bonnie++ tests I made to test the performance:
# bonnie++ -s 256m -d /mnt -u 0 -r 0
and
# bonnie++ -s 1g -d /mnt -u 0 -r 0
I also tried 3 of the drives in a RAID 5 setup with gave similar results.
Is it me or are the results poor?
Is this the best I can expect from the hardware or is something wrong?
I would appreciate any advice or possible tweaks I can make to the system to make the performance better.
The block I/O is the thing that concerns me as mostly I am serving a 650MB file via samba to 5 clients and I think this is where I need the speed.
Plus I am hoping to run some virtualised guests on it eventually, but nothing too heavy.
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
That onbard raid is fakeraid..so when you dialup raid 5 you effectivly put hte hdd's in pio mode since ALL data has to be routed through your cpu. Please get a raid card from HP or go get a 3ware card so you ahve real hardware raid.
fake and real raid chpsets: http://linuxmafia.com/faq/Hardware/sata.html
Why using fakeraid at all is bad: http://thebs413.blogspot.com/2005/09/fake-raid-fraid-sucks-even-more-at.html
MDM under linux is kernel raid that does not use a binary driver..however you don't want to do ANY software raid 5.
Thanks William,
I am no expert on RAID, so you have opened my eyes to somethings I wasn't aware of.
I am considering disabling the onboard RAID in the BIOS and re-installing CentOS and configuring the 4 drives as RAID 10 just to see what the performance is like.
Or I may purchase a card as you advise. Would I benefit from buying a SCSI/or SAS card and drives for my requirements? Basically the main role of the machine is to serve a ~600MB file via samba to 5 Windows XP cient PC's on a gigabit network.
If all your doing is serving a single file to a handful of PCs then a 2 drive mirror will be more then enough.
That is what I currently have setup on the old server, but it only has 1GB ram and AMD Duron 1300MHz CPU.
The performance on the clients gets slower as the file size grows and now it has got very slow - hence the new server.
Sounds like the file is getting more and more fragmented and the io is turning into random io over it.
Once a week disable access to the file, copy it to a new name then move it back over the top of the old one and that'll defrag it.
You should stick with the OS RAID though as the onboard RAID will bring nothing but pain.
That is what I have read. So understood :-)
For sequential IO expect 60MB/s read and 40MB/s write (with the drive's write cache enabled) per drive. Random IO is an order of magnitude less.
Should that be OK for my needs or for the clients to be happy should I be wanting more? what figure should I be looking at?
That's what to expect with standard file io operations (4k) some apps use larger ios so they will get better throughput (backups 64k, video editing 128k+) which can max the network throughput (115MB/s on Gbe).
Sorry for all the questions and thanks for the
Not a problem, that's what the lists are for!
-Ross