24 4TB optimal Vdev allocation

[tbaror]

Hi All,

I am about to install new system with following spec below
I would like to create one big pool and from there dived it to dataset , My question is what would be best
balanced config throughput(MB/s/IO) ,Protection ,Space in terms of Vdev creation
My thought was create 4 vdev of 6 drives raid Z2
Please advice
Thanks

Chassis 4U SuperChassis 846BE1C-R1K28B 1
Motherboard Single Socket Motherboard X10SRL-F 1
Processor Intel® Xeon® E5-1620V3 Processor 3.50GHz (3.60GHz,10MB,140W) 4C/8T x 1
Memory 32GB 2133MHz DDR4 ECC Reg CL15 LRDIMM x8
HBA LSi SAS HBA 9300-8i SGL x1
SSD Samsung 850 Pro 512GB SATA SSD x 4
HDD Seagate 4TB Enterprise NAS SATA 6Gb/s 128MB Cache 3.5" x 24
Network Card Intel® Ethernet Converged Network Adapter X710-DA4 x1

 

[jgreco]

4 vdevs of 6 drives in RAIDZ2 is probably okay. You end up with 16 of 24 drives usable space. However, you can also consider two 11 drive RAIDZ3 vdevs and hold two disks back as hot spares. This has slightly less performance, but allows ANY three drives to fail AND actually has the replacement disks sitting there ready to go.

With a RAIDZ2, you lose one drive and you are one drive away from having lost redundancy, and you need to run out to the store and get another drive quick.

With the RAIDZ3 I suggested, you lose one drive, and the array says "Oh, fail, I guess I'll sub in one of the spares." Then you get a notification that you need to replace a drive, but you don't have to panic, because there's another spare also ready and waiting. Even if the replace/resilver fails, you still have substantial redundancy to fall back on. Same number of drives as your RAIDZ2 array. Somewhat less performance. Much better resiliency.

 

[gpsguy]

A month ago, you were looking for a SAN solution, with similar components. Is this the same system?

If so, striped mirrors (consider 3 way mirrors), would give you better performance.

 

[jgreco]

Three way mirrors is the way to go for high performance with good redundancy characteristics.

 

[tbaror]

A month ago, you were looking for a SAN solution, with similar components. Is this the same system?

If so, striped mirrors (consider 3 way mirrors), would give you better performance.

Hi ,
Yes same system , how do i get 3 way mirrors ?
Thanks

 

[jgreco]

I think it's configurable via the GUI in the wizard. I don't recall for certain; I do it by hand since I actually started the array out as a bunch of two way mirrors. If you have trouble figuring it out, squeak and I'll bring up one of the FreeNAS test VM's here and find out for certain.

 

[tbaror]

Thanks , i will