4 disk Western Digital (WD10EZRX), What is the Best ZFS recommendation?

[crisman]

Hi,

I'm building a NAS with the following:

Case: standard Micro-ATX case
MB: Asus E45M1-M PRO
Memory: 2 x 4Gb Kingston CL9 PC3-10666 (1333 MHz)
FreeNAS boot disk: Sata DOM Kingspec 4 Gb
HD: 4 WD Caviar Green 1 TB SATA Hard Drives (WD10EZRX)

Could someone help me on the best ZFS setup for this system?

Regards,
Crisman.

 

[leenux_tux]

Crisman,

Depends on what it is your going to use the storage for......

Backups ? Music ? Movies ? Will you be streaming movies/music around the house ? Will you be using the system for hosting Virtual Machines via iSCSI or NFS ? Or, all of above ??

With four drives there are a number of "setups" you could go for, RAID0+1, RAIDz with a hot spare (think RAID 5, three drives, one hot spare). It all depends on your requirements. Speed ??? More storage capacity ?? (different RAID configs will give different amounts of usable disk space)

Describe what it is your trying to achieve, then you might get some good examples.

 

[crisman]

Crisman,

Depends on what it is your going to use the storage for......

Backups ? Music ? Movies ? Will you be streaming movies/music around the house ? Will you be using the system for hosting Virtual Machines via iSCSI or NFS ? Or, all of above ??

With four drives there are a number of "setups" you could go for, RAID0+1, RAIDz with a hot spare (think RAID 5, three drives, one hot spare). It all depends on your requirements. Speed ??? More storage capacity ?? (different RAID configs will give different amounts of usable disk space)

Describe what it is your trying to achieve, then you might get some good examples.

Hi leenux_tux,

At this time is mainly for backups, what combination of RAID-z I should consider? of course speed is important but I prefer now capacity.

I've also a chance to add one more hard drive, do you think its a good idea?
What you personally think about these WD (WD10EZRX) hard drives?


Thank's.

 

[ben]

RAID 10 (two RAID 1s striped) or RAID Z2 are the "ideal" configurations for four disks that use them all, or RAID-Z with a spare. RAID 10 or RAID Z will have somewhat better performance, RAID Z2 better protection. All of those uses will have the same space available. If you have one more drive, RAID-Z (4+1) is a much higher capacity option than what you have with 4 drives, so if you want capacity, that's a good choice. I have no opinion on that particular drive.

 

[crisman]

RAID 10 (two RAID 1s striped) or RAID Z2 are the "ideal" configurations for four disks that use them all, or RAID-Z with a spare. RAID 10 or RAID Z will have somewhat better performance, RAID Z2 better protection. All of those uses will have the same space available. If you have one more drive, RAID-Z (4+1) is a much higher capacity option than what you have with 4 drives, so if you want capacity, that's a good choice. I have no opinion on that particular drive.

Hi ben,

When you say RAID-Z (4 + 1) you mean 4 data disks plus 1 hot spare?
I've read somewhere that for RAID-Z the best combination would be 3, 5, 9 ... Disks and not 4 has you mentioned! Because of the 128 KiB stripe size.


As seen on this message:

sub.mesa wrote:
As i understand, the performance issues with 4K disks isn’t just partition alignment, but also an issue with RAID-Z’s variable stripe size.
RAID-Z basically works to spread the 128KiB recordsizie upon on its data disks. That would lead to a formula like:
128KiB / (nr_of_drives – parity_drives) = maximum (default) variable stripe size
Let’s do some examples:
3-disk RAID-Z = 128KiB / 2 = 64KiB = good
4-disk RAID-Z = 128KiB / 3 = ~43KiB = BAD!
5-disk RAID-Z = 128KiB / 4 = 32KiB = good
9-disk RAID-Z = 128KiB / 8 = 16KiB = good
4-disk RAID-Z2 = 128KiB / 2 = 64KiB = good
5-disk RAID-Z2 = 128KiB / 3 = ~43KiB = BAD!
6-disk RAID-Z2 = 128KiB / 4 = 32KiB = good
10-disk RAID-Z2 = 128KiB / 8 = 16KiB = good

 

[ben]

I mean five, the plus one I intend as parity. Sorry for the confusion.