disk layout recommendation

[HJR]

hello,

i have an 3u enclosure with 16 hot-swap drivebays.
i polutated 14 of them with 2tb sata disks and 2 polulated with 120gb ssd disks for zil.
(core i3 cpu @ 2.8 ghz, and 32gb ecc memory)

all are connected to an lsi 9211 8i sas controller with an sas expander board (also lsi).

it works great and freenas sees all disks.

now i made a raidz2 vdev on it with 1 hot spare. thinking this would be a great setup. 14 data disks. 1 spare and 2 parity makes 11 disks of 2tb netto storage.

now i read on several posts not to add more than 10 disks in a vdev.... oooopssss...
so i read all of you recommend raid 10 or a striped mirror.

so i want to put 2 disks in a mirror and do that 7 times. so i will get a stripe of 7 mirrors. (14 disks). is this a recommended setup?
or should i create to stripes of mirrors (for example 1 stripe of 3 mirrors and 1 stripe of 4 mirrors)

i use the storage as iscsi for vmware and afp/nfs/cifs storage for video/data

 

[jgreco]

ZFS will automatically stripe the data over the available vdevs (slightly more complicated but true enough for discussion).

For speed, mirrored disks are generally faster than RAIDZ, but the redundancy is less.

For redundancy, RAIDZ disks are more reliable than mirrored. However, RAIDZ2 works best when you have reasonably small numbers of components in a vdev, and for best performance, you want a power-of-two number of devices plus parity. You can have 8+2 devices in RAIDZ2 (10 disks total), or 8+3 devices in RAIDZ3 (11 disks total) for a more fault-tolerant 16TB array.

You can also put your 14 drives in a RAIDZ3 (11 data plus three parity), which gives you the best space utilization and redundancy characteristics. It is commonly felt that that's a bit wide for a vdev, but not really unacceptable.

For best speed, create seven mirrored vdevs and put them into a pool. ZFS will do the equivalent of striping them for you, and that's about as fast as you can get with spinny disks.