3Ware Escalade 8506-8 card, which raid to choose?

[davebraco]

I was given some material to create a server file for hosting my home video files :

- Asus PSCH-L Pentium IV 3Ghz (32Bit) 3,5Go Ram (with 4Go onboard ethernet is disabled)
. onboard PCI-X Intel 82547GI ethernet
- PCI-X 3Ware Escalade 8506-8
- 6 1To Disks with two free bays for a possible log/cache disk.
(plus 80Go disk on board port to boot FreeNas)

I've read the FreeNas guide and, sadly, it seems that ZFS should be avoid on this configuration.

My idea with to get a Raid5 volume (one drive can fail). The tw_cli command report that the card is configured in JBOD.

Is it better to build a hardware raid volume using the tw_cli command or create a volume using the FreeNas web interface in UFS? FreeNas GUI only interesting proposal is a raid3 with UFS on 5 disk.

If two additional drive of 250Go are added for log and cache. Could I use ZFS as a reasonable speed?

Thanks in advance for your help!

 

[davebraco]

- This card doesn't allow more than 2To with hardware raid.

- I made some test with ZFS raidz and UFS raid3, ZFS is definitly not recommended for my config but UFS gave me the results I expected : by FTP, ~65Mo/s writing, ~95Mo/S reading.

- But it seems that UFS raid3 only function with a odd number of disks and 5 disks is the maximum allowed (I've tried 7 disks without success)

I will give a look at FreeNas 7...

 

[louisk]

I expect your problem wtih ZFS is because you were only using a single vdev. If you put everything in a single RAID5 vdev, you will have the performance of a single spindle. If you want more performance, you will need multiple vdev. For example, if you have 6 spindles, you can create 2 RAIDZ vdev of 3 spindles each. This will give you the performance of 2 spindles. You could also create 3 mirror vdev of 2 spindles each, this will give you the performance of 3 spindles.

(ZFS stripes data across the vdevs in the pool, hence the additional performance)

 

[davebraco]

louisk, thank you for your advice. I will try your proposal.

I will also get an other motherboard which have a 64bit CPU and DDR2 memory which will allow me to get at least 6G of Ram.