BUILD I upgraded....

[Michael Schultz]

So I inherited a couple dell poweredge r810's and decided to make myself a freeNAS box. I have pretty much everything but the drives. It's a bit ghetto having the drives in another chassis, but not too bad.

4x Intel(R) Xeon(R) CPU E7- 8837 @ 2.67GHz - 32 full cores
256GB ddr3 10600r
3x LSI Logic LSI00188 / SAS9200-8E
silverstonetek rm420 20 drive 4u case - 5x sas
seasonic x850 solely for the drives (may need to upgrade this once I get all 20 drives)
2x 10GBASE-T
2x 120 ssd via dell PERC controller raid1 for boot drive

Other than media streaming/gathering, including 4k content, it will be the primary storage for a separate vsphere box over a dedicated 10G port. Write speed is relatively important here..

I purchased 4x seagate archive 8tb drives because they were 60% of the price of other 8tb drives, but reading up on what drives are good in a NAS, I think I made a mistake. 1 out of the 4 came DOA according to SMART tests, but that doesn't really say anything about the quality of the drives by itself. Drives can come DOA no matter what company you get them from.

So my question is essentially, what class of drive do I need to get to get the best performance out of my setup. Will my over abundance of ram help me ignore all the shortcomings of the crappy seagate archive drives, or should I just bite the bullet and go for WD reds? If I am upping my cost significantly anyway, what advantages (if any) would I get if I went further and got 20 enterprise class 8tb drives with 256mb cache?

 

[Mirfster]

Will my over abundance of ram help me ignore all the shortcomings of the crappy seagate archive drives, or should I just bite the bullet and go for WD reds?

RAM is not going to help save a bad drive, regardless of who makes the drive. ;) Not everyone here runs enterprise class drives, but WD Reds and HGSTs seem to be the most preferred manufacturers.

If I am upping my cost significantly anyway, what advantages (if any) would I get if I went further and got 20 enterprise class 8tb drives with 256mb cache?

I run HGST Enterprise 7200 RPM drives; but that is "against the grain" since for the added heat and power consumption the gains are not supposed to be worth it. I still do it anyways... :) I am not recommending you run or even pay the extra costs for Enterprise Drives though. See what the consensus is and use that towards your decision.

Other than media streaming/gathering, including 4k content, it will be the primary storage for a separate vsphere box over a dedicated 10G port. Write speed is relatively important here..

You may be looking at mirrored vdevs to get the most speed here. If iSCSI is in your view, then take some time to read the posts regarding it so you get a better understanding as to what is entailed and avoid any pitfalls. With the amount of RAM you are talking about L2ARC should be considered as well.

 

[joeschmuck]

I agree mostly with @Mirfster except for...

With the amount of RAM you are talking about L2ARC should be considered as well.

An L2Arc has a very specific purpose and most folks don't benefit from it unless they are accessing databases and spreadsheets frequently (repeating access to the same data) and based on your requirements, you wouldn't benefit at all.

A few points I'd like to make to answer your questions...

what class of drive do I need to get to get the best performance out of my setup

It depends on how much money you want to spend. On the high end some SSD's would peak your performance in a RAIDZ2, well for what you want. On the more reasonable side, depending on your storage requirements, maybe several mirrors of the 8TB drives (two or three vdevs of three 8TB mirrors). You could go with two drives in a mirror but that means you can only allow 1 drive to fail without data loss and 8TB drives take a long time to resilver so it's a high risk to the pool. This is why I like all my 2TB drives, resilvering takes much less time until my pool is healed.

And as @Mirfster said, if you are looking at iSCSI, do your homework or you will likely be sorry as many folks do not build a fast enough system and things crash. Mirrored drives comes to mind.

 

[Arwen]

I own one of the Seagate 8TB Archive / SMR drives. It's used for backups
exclusively, meaning it's basically a write only application. (With a scrub
before or after each backup, which is the only reading done until the need
for a restore.)

These Seagate 8TB Archive / SMR drives have very irregular write performance.
For my backups, I tended to get an average of 30MegaBytes per second using
Rsync. No where near what the source should support, (>100MegaBytes per
second I would guess).

Plus, since they relocate ALL data, something as simple as streaming a 4K
movie may actually have quite a few head seeks. Thus, reducing your read
performance.

But, with careful planning of your VDevs, it may be possible to make a usable
configuration with these Seagate 8TB Archive / SMR disk drives.

I personally don't recomend these be used in any RAID type environment
except striping.

 

[Mirfster]

But, with careful planning of your VDevs, it may be possible to make a usable
configuration with these Seagate 8TB Archive / SMR disk drives.

I personally don't recomend these be used in any RAID type environment
except striping.

Personally, this speaks volumes of information....

 

[Arwen]

The comment about not using them in any RAID environment is also due
to TLER, (Time Limited Error Recovery). These don't support that feature.
(Or at least mine with it's existing firmware does not.) So for hardware
RAID, these Archive / SMR would likely be trouble makers, dropping out of
RAID sets when a block is bad but recoverable.

For ZFS software RAID, (Z1-3 or Mirroring), lack of TLER may cause slow
downs when encountering a bad but recoverable block. Even though the
data is redundant.

So, using them for Archive purposes in a Stripe may make sense. (Of course
with protected source data, or good backups.)