SCSI, SAS, SATA2, SSD ...

[CSQuake]

Hi guys,

If money was no object, which storage solution would you choose for speed?

SATA2
SCSI
SAS
SSD

This is to be primarily a gaming rig. And the drives can be raided for extra speed.

 

[Tweakin]

SAS

 

[Rubycon]

SSD is not an interface.

SSD disks with SAS interface would be the best choice, however. For current available technology SAS 15k is the best. If you have bulk (alternator sized) requirements you want FCAL. (Fibre Channel)

I have SAS 15k arrays on my daily use workstation and its performance is satisfactory. (but like everyone else I want to go faster hehe)

 

[taltamir]

http://www.ocztechnology.com/p...es/ocz_sata_ii_2_5-ssd
This is what I would say the fastest drive is today.
500$ for 32GB version. 1200$ for 64GB version. SATA2 SSD drive.

15k SAS reaches ~145MB/s vs 120MB/s on the SSD sequential speeds and similar drive capacities, but 15K SAS only get seek times of 3.5-3.8ms, while the SSD have less then 0.1ms.
SAS is actually cheaper then SSD. If money is no issue, RAID0 some of those amazing OCZ drives. (Or, use 2 of them, one as a dedicated OS, one as a dedicated gaming drive... and don't bother with nasty raid drives and issues)

As a gaming rig with no money limit you are probably overclocking. The 15K drives would generate far too much heat.
They will also be loud, take lots of power, take lots of space, and be a pain in the ass to connect to a motherboard and boot from (you will have to get a controller card, which will probably not fit with the triple SLI / Quad Crossfire someone with no money limit would have; not to mention the hoops you would have to jump through to get a SAS controller to boot windows).

 

[Rubycon]

I have no issues with enterprise grade RAID stuff. I need to have >500MB/S STR for at least 10-100GB streams. 2GB burst of ~2GB/S possible with the cache. Far, far faster than the OCZ product which is SATA. When they have 128GB+ SSD SAS drives in 2.5" format I'll buy them.

Heat is never an issue with any mechanical drive if they are properly mounted. SAS/SCA bays always have forced cooling and maintain satisfactory drive temperatures.

 

[taltamir]

From reading about it a little bit it seems that:
1. SAS has 1.5, 3.0, and 6.0 Gbps, and SATA has 1.5,3.0 Gbps, and SATA drives can be connected to SAS controllers, they are very similar, SAS just has some extra features (like error corrections and the like).
2. The fastest single drives are just under 150 MB/s. To get 500+ you have to use a raid array. And for that either SAS or SATA would do. (you can connect either SATA or SAS drives to high end SAS raid controllers and have them be RAIDed together)

So, unless I misunderstood something, there is no real reason to use SAS over SSD. (especially if you use a proper file system like ZFS + RAIDZ2)

EDIT: But in retrospect, its not a matter of the technical specs on the interface, but rather, what a drive connected to such an interface is designed to do. SAS drives have much higher MTBF ratings due to higher quality constructions. It stands to reason that they would also be optimized for multiple continuous rapid access. But this wouldn't mean that the SSD drives need to be SAS, but rather, that SAS SSD drives would likely be designed with different controllers then the SATA ones, and thus perform differently.

 

[CSQuake]

So the census so far is to get SAS controller and 2 SATA2's in Raid 0, or 2 SSD in Raid 0. Any more views?

 

[Rubycon]

SAS is an interface - SSD is a device.

SAS controllers can drive SATA and SAS drives so they are a better investment if you call it that. They are more expensive in the entry level realm however comparable mid range (areca) controllers cost the same whether SAS or SATA which is a no brainer. You can even run SAS and SATA drives simultaneously on the same controller. (there are rules with certain expanders/backplanes which must be followed however)

 

[Lorne]

SAS SSD, No SATA what so ever.

 

[imported_wired247]

Originally posted by: CSQuake
So the census so far is to get SAS controller and 2 SATA2's in Raid 0, or 2 SSD in Raid 0. Any more views?

not really... it sounds like you came up with that on your own.

Buying a SAS controller would be a huge waste if you were only going to get 2 drives to go with it.


What's your actual budget?

You can easily spend $5k on hard drives and RAID controllers alone.


Hell I spent close to $600 on my RAID array which is peanuts compared to rubycon's which was clearly much more.


Faster hard drives don't help with games, except to shave a few seconds off of load times.

That's right, you could spend $5000 and shave maybe half the load time off. So... what was your budget again?

 

[CSQuake]

£600 or $1200.

So let's hear your words of wisdom wired

 

[taltamir]

i thought you said money was no object
Ok with that kind of budget you should probably go for the WD 640GB drive. It is very fast and relatively cheap (129$, needs no controller).

 

[CSQuake]

Not fast enough.

 

[CSQuake]

How about this: http://www.scan.co.uk/Products...sp?WebProductID=752317

73.4 GB Seagate ST373455SS, Cheetah 15K.5, SAS, 15000 rpm, 16MB, 3.5 ms

Will i be able to Raid0 2 of these without an SAS controller? And will it be fast?

 

[taltamir]

isn't your computer budget 600£ for the whole thing? thats 107£ PER DRIVE. you want two of those plus a controller and its over a third of your money going towards hard drives alone. You would get much better performance by getting better RAM, CPU, or GPU rather then HDD.

 

[CSQuake]

£600 for the HDD's, I can stretch to more, but if I get great speeds with nearer £600 then that is fine.

So I do need controllers with 2 of these SAS drives?

 

[Rubycon]

Originally posted by: CSQuake
So I do need controllers with 2 of these SAS drives?

Yes - unless the motherboard has a SAS host. SATA drives can be attached to SAS hosts but SAS drives cannot be attached to SATA hosts. Not fair, but that is how it is.

 

[CSQuake]

Cheers Ruby.

Is this any good: http://www.scan.co.uk/Products...sp?WebProductID=554484

(LSI MegaRAID 8308ELP 8 Port SATAII/SAS PCI-E Controller)

The prices fluctuate ridiculously, so I'm guessing I don't need something that costs £500+ for just 2 SAS drives?

 

[lopri]

I have to agree with wired247 in that it's kinda questionable investment getting a SAS card for just 2 physical drives. (And I believe you mentioned that it's for gaming.. ?) Just get fast SATA drives and do RAID0 with on-board controller. On-board controllers from Intel/NV are surprisingly good and you will need a very expensive controller card to be meaningfully faster.

Take a look at this review comparing a $400 SAS controller with an ICH9R.

http://www.tweaktown.com/revie..._8_port_sas/index.html

 

[imported_wired247]

I would spend between GBP 150-200 on the controller (HARDWARE raid with a good I/O processor and some RAM cache), SATA II will be more than enough for you, and then spend the rest on 4 of the western digital WD6400AAKS (or WD3200AAKS) and put them in RAID-5.

For the home user there's no reason at all for you to need more than 4 drives. Choosing 4 should fit your purposes.

It will be very fast, and plenty of storage. Those high density platters offer very good throughput and getting 4 of them negates any penalties that you would incur from having only 2 drives in a RAID-0 array.

For you I would choose hard drives that have better throughput, rather than simply the fastest 15krpm drives which offer the best seek times. Seek time won't matter nearly as much if you aren't running a heavy loaded file server (unless someone wants to correct me).

High throughput is the reason for going with the 7200RPM drives with high density platters.


You could put them in RAID-0 but it won't give you much more speed, and your chance for array failure quadruples. In RAID-5, even if a drive stops working you can just order a new one, pop the bad one out, and replace it with the new one. Nice and easy.

If you do choose RAID-0 then I would tell you to get a 1TB drive, internal or external, for periodic backups of your RAID-0 array.

Those are my words of wisdom, of course it's your money so you should do whatever you want. I know I always do

 

[taltamir]

I agree with wired's observations. He summed it up neatly.

There is one thing I want to add. Are you going tri/quad GPU? (if your HDD budget alone is 1200$ then I would guess you are...) if so, then you would likely not have ROOM to place that many drives and definitely no room to plug in the controller. If you are stuck with the motherboard controller, then RAID5 will give ATROCIOUS performance. On the other hand, RAID0 would put your data at a huge risk. But RAID1 just wouldn't be that fast.

So I would suggest RAID0 and an external backup. Use software suite like www.secondcopy.com to keep the external drive up to date. If one of the RAID0 drives fail, you could replace it, rebuild the array, and restore your data (you would have to reinstall windows, but at least your stuff would be safe).

If you are really paranoid about your data, you could build a ZFS/RAIDZ fileserver (i am, i ordered the parts yesturday). And get protection against drive failure, controller failure, power failure, and silent data corruption.
http://en.wikipedia.org/wiki/ZFS
http://opensolaris.org/os/community/zfs/

 

[CSQuake]

Awesome advice, many thanks

 

[heymrdj]

Originally posted by: wired247
For the home user there's no reason at all for you to need more than 4 drives. Choosing 4 should fit your purposes.

I beg to differ lol. I have a 4 drive (non RAID) array at 920GB formatted space, but it's only got 100GB left. So again i'm looking to expand.

500GB, 320GB, 160GB, 40GB.

 

[Rubycon]

Number of drives depends on personal use. With a decent controller the scaling of performance is nearly linear up to a rather large number of drives before leveling off. (or reaching the limit of the bus in which it's connected to!)

There is NOTHING wrong with purchasing a high end controller - even for a SINGLE drive! Performance will be stellar with a strong IOP with lots of cache and full write back policy. The only downside is you will want to put as many drives on it as space permits. And that is where it can get expensive.