Re: Openfiler iSCSI RAID5

IZ325 · ‎07-31-2010

Currently I have a 1TB SATA disk for datastore in my lab and have 6 servers running on it. It is slow to access. If I add other disks and use Openfiler to create RAID5, will it be much faster? Thanks.

golddiggie · ‎07-31-2010

How are you planning on building the system for openfiler? IF you're going to use a hardware resource, with hardware RAID (a RAID controller with battery backed cache, or at least the option for such) then it could be faster, depending on how many spindles you use. IF you're talking about just adding more disks to the host server, and using the VMDK's on a system to create it, then I seriously doubt you'll have any performance benefit from such as configuration. You're always better off using hardware RAID over software RAID. You also need enough spindles under RAID5 to offset the penalties in performance. RAID 10 would give you better performance at a lower spindle cost.

Right now I have eight VM's running on my current ESXi 4.1 host using a RAID 1 array (two 7200rpm SAS drives) that's in the host. I think if you went to SAS drives, over SATA, you'll have better performance. Even if you go to 7200rpm SAS drives. If you're already wanting more performance, then get a hardware RAID controller, sufficient number of SAS drives, and use RAID 10 (if less than six to eight drives) for the array. If space isn't the issue, but performance is, then go to 10k rpm SAS drives, and still use RAID 10 (hardware) on the array.

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VMware VCP4

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Jackobli · ‎08-01-2010

You're always better off using hardware RAID over software RAID.

Seriously? I doubt…

Based on a dedicated file server, the cpu may easy be powerful enough to satisfy a GBit Ethernet. Together with a powerful cpu, you got also file system caches helping.

Internal controllers on an ESXi host are a different thing.

IZ325 · ‎08-01-2010

My server's CPU is quad core Xeon with 8GB RAM, plus a Gigbit switch so one 1TB disk is the bottleneck. I know the hardware RAID is faster but expensive. Probably software RAID is my first try. BTW, for software RAID solution, which software has better performance, Openfiler, FreeNAS or something else? Thanks.

Jackobli · ‎08-01-2010

My server's CPU is quad core Xeon with 8GB RAM, plus a Gigbit switch so one 1TB disk is the bottleneck.

You cannot use the same machine for ESXi and for a NAS. You need an additional server which you have to setup for NFS or iSCSI.

On that server you may use software RAID.

>I know the hardware RAID is faster but expensive. Probably software RAID is my first try. BTW, for software RAID solution, which software has better performance, Openfiler, FreeNAS or something else? Thanks.

I don't know exact numbers for iSCSI and NFS, FreeNAS is often blamed for it's poor Samba/CIFS performance.

I don't need any gui additions, so I prefer a plain linux distro and use ssh for management.

In case of hardware controllers, I prefer Areca. They are building controllers with large caches (up to 4 GByte) and have direct ethernet access for RAID configuration and alerting (OS independant).

walkerjg · ‎08-01-2010

I will be out of the office until Tuesday, August 10th. If this is an urgent issue please contact Peter Redhead at Peter.Redhead@newschool.edu.

James Walker

Network Engineer

The New School

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walkerjg · ‎08-01-2010