FlexRAID Support Forum

Hardware => Buying Recommendations => Topic started by: Brahim on December 04, 2013, 02:59:52 pm

Title: Hard Drive recommendation for Transparent RAID users
Post by: Brahim on December 04, 2013, 02:59:52 pm
For users running Transparent RAID and looking to buy new hardware, an often reoccurring question is which drive to buy.

Transparent RAID favors disk with low access time - especially for the PPU disks.

As such, it is a good idea to consult the following resources:

Here are some sample charts comparing the WD 4TB Black drive against some other drives.
Note how the RED drives don't fair too well in these benchmarks.
(http://forum.flexraid.com/index.php?action=dlattach;topic=3111.0;attach=2424;image)

(http://forum.flexraid.com/index.php?action=dlattach;topic=3111.0;attach=2426;image)
Title: Re: Hard Drive recommendation for Transparent RAID users
Post by: shaun.arundell on December 04, 2013, 04:13:45 pm
Brahim

I have a load of WD  3TB Reds, IS it worth will replacing the WD Red PPU(s) with disks with better access times (segate etc) ?.
Will that make a substained difference on writes or will the WD red  DRU wirte times dominate ?

shaun
 
Title: Re: Hard Drive recommendation for Transparent RAID users
Post by: Brahim on December 04, 2013, 04:37:36 pm
If buying new disks, yes, it is worth going with faster disks (lower access time) for PPU.
So, for your next disk upgrade, buy faster disks and make them PPUs and move the RED disks to DRU duty.

It is best to wait and see how the new performance mode fairs out though.
It does improve the performance of disks with high access time in sequential operations.
So, unless you have a heavy concurrent workload, this might be good enough.

The difference between disks with low access time vs high access time is significant.
I have setups that reach performance up to 65% of source disk sustained write speed in TCQ and energy efficiency mode. Compare that to other users only getting as low as 25% for the same settings.
It is all about access time and in particular when in energy efficiency mode.
Title: Re: Hard Drive recommendation for Transparent RAID users
Post by: SentinelBorg on December 05, 2013, 07:54:32 am
The Western Digital SE 4TB should be a good choice for parity disks. Their performance is somewhat in between RE and RED on the level of the Black, but they are much cheaper than the RE and are allowed for continuous operation in storage systems unlike the Black.
Title: Re: Hard Drive recommendation for Transparent RAID users
Post by: Brahim on December 05, 2013, 09:36:00 am
The Western Digital SE 4TB should be a good choice for parity disks. Their performance is somewhat in between RE and RED on the level of the Black, but they are much cheaper than the RE and are allowed for continuous operation in storage systems unlike the Black.

Looking at the ATTO write benchmarks below (taken from here (http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/61717-western-digital-se-4tb-hard-drive-review-single-raid-4.html)), you are correct that the SE are a good compromise.
The Seagate Barracuda is a better choice though.
(http://forum.flexraid.com/index.php?action=dlattach;topic=3111.0;attach=2437;image)
Title: Re: Hard Drive recommendation for Transparent RAID users
Post by: dscline on December 05, 2013, 09:53:59 am
The Western Digital SE 4TB should be a good choice for parity disks. ... and are allowed for continuous operation in storage systems unlike the Black.

Though wouldn't a parity disk only be active during writes and RAID tasks like verify?  I wouldn't think they would normally be operating more than, or even as much as, a typical desktop OS drive, so the 24x7 blessing wouldn't seem that critical.  I would be more inclined to use a 7200 rpm drive such as the Black for parity, despite not being targeted for server or NAS use.
Title: Re: Hard Drive recommendation for Transparent RAID users
Post by: terrastrife on December 05, 2013, 10:26:50 am
I would still buy the Black over an Se, currently the Se is based on the original Black design, the Black has been updated and is faster, not to mention much cheaper.
Title: Re: Hard Drive recommendation for Transparent RAID users
Post by: Brahim on December 05, 2013, 11:11:39 am
@dscline
Great point. If one's array is not write heavy, then the PPUs will experience lot of idle time.
The PPUs still need to be fast for when they are needed.

@terrastrife
Yep, price/performance wise, the WD Black wins.
The argument for the SE would supposedly be reliability. This, however, needs to be backed by numbers.
We all know that reliability can sometimes be a case of "luck of the draw".
Title: Re: Hard Drive recommendation for Transparent RAID users
Post by: dscline on December 05, 2013, 12:24:45 pm
the Se is based on the original Black design
Yeah, my bad, I had it in my head that the SE was a 5400 RPM drive. Which is silly, as there wouldn't be much to differentiate it from the Red.  Though from what I remember when I was looking at them, their error rates & load cycles weren't any better than the consumer drives, so I didn't really see the point in paying a premium for them.
Title: Re: Hard Drive recommendation for Transparent RAID users
Post by: shaun.arundell on December 05, 2013, 09:01:22 pm
I just brought a few WD 3TB Blacks today and will post some  TRAID disk benchmarks tonight and I hope to run a couple of copy  scenario's over the weekend

1. 1 Black PPU + 1 Black DRU
2. 2 Black PPU + 1 Black DRU
3. 1 Black PPU + 1 RED DRU
4. 2 Black PPU  + 1 RED DRU
5. 1 RED PPU + 1 Blakc DRU <= proably wont bother

Each scenario will have a 20hr raid parity construction phase so It's going to take some time

shaun
Title: Re: Hard Drive recommendation for Transparent RAID users
Post by: terrastrife on December 05, 2013, 09:30:35 pm
Each scenario will have a 20hr raid parity construction phase so It's going to take some time
Urm, you may have controller bottlenecks if it's taking 20 hours. My Verify Sync takes 12 hours offline and 15 hours online.
Title: Re: Hard Drive recommendation for Transparent RAID users
Post by: shaun.arundell on December 05, 2013, 09:55:30 pm
forgive me for to exaggerating. Those times would be about right for me too.

shaun
Title: Re: Hard Drive recommendation for Transparent RAID users
Post by: Brahim on December 06, 2013, 12:54:42 am
...
Each scenario will have a 20hr raid parity construction phase so It's going to take some time

shaun
Why bother computing parity if this is just for testing?
Just initialize by doing nothing. The parity might not be correct, but that won't affect the tests.
Title: Re: Hard Drive recommendation for Transparent RAID users
Post by: shaun.arundell on December 06, 2013, 03:51:17 am
Ah Ah - that will say a lot of time
Title: Re: Hard Drive recommendation for Transparent RAID users
Post by: IVB on December 11, 2013, 08:46:20 pm
FYI for the avnation.tv guys, this is Vivek (dude from tonights podcast), this is what I referred to on the 12/11 episode. The product I use is tRAID, aka Transparent RAID, one of the product offerings.

(Sorry Brahim, wanted to provide some written context so people coming here without checking my Google+ page would know what I was talking about)
Title: Re: Hard Drive recommendation for Transparent RAID users
Post by: Dizzy49 on July 15, 2014, 01:07:09 am
I'm building a new server from scratch, so I'm trying to figure out the best drives to buy.  Right now I have some Samsung Green drives, couple Seagate, and WD Red.  I'm looking at 12 drives to start (10 DRU, 2 PPU) and move to 24 drives (20 DRU, 4 PPU).  I am assuming a 5-to-1 DRU/PPU ratio is a good ratio.

Right now it looks like there is a $30 premium to go from WD Green to WD Red, and a $60 premium to go from WD Red to WD Black.

For performance on a budget it appears the WD Green are the way to go for the DRU, and WD Black for PPU. (10 @ $190, 2 @ $280 = $2460)
For a price/performance mix, WD Red for DRU, and WD Black for PPU. (10 @ $220, 2 @ $280 = $2760)  $300 increase from Budget
For all-in performance WD Black all the way. (12 @ $280 = $3360)  $900 increase from Budget, $600 from Price/Performance

Anyone had any experience with the Hybrid drives?  Did we get some data from shaun.arundell?  I'd like to put some hard numbers along side the costs to see if the performance justifies the cost increases.


Title: Re: Hard Drive recommendation for Transparent RAID users
Post by: AndreasK on March 09, 2015, 11:24:15 pm
you could also replace the Blacks with Red Pro or Se if they cost about the same. you get similar performance with better reliability rating. But in general I think the 5400RPM DRU with 7200RPM PPU is the best price/performance mix.

Regarding hybrid drives, remember that the SSD part doesn't act as a landing disk but stores the most commonly accessed data, so this would only be of benefit if you are doing lots of reading of the same data.