Web Hosting Talk : Web Hosting Main Forums : Dedicated Server : Raptor 10k SATA drives vs. SCSI 10k

[hostmaniac]

I'm thinking of buying a bunch of Raptor 10k drives for a database intesive server because of cost factors. I looked at a few reviews on the Raptor SATA drives which deliver 10k RPM, not bad. Is anyone out there using these drives? I'll save a whole bunch if I opt for these drives as opposed to a SCSI setup.

Also how much performance gain is there from placing the database on different drives than the OS?

[turnkeyinternet]

I'm usualy very PRO sata based on price/performance. But only if its 1 or 2 disks in the system (and only if you use quality ones, like seagate, avoid anything with a 1 year waranty as that means its not even rated for datacenter use!).

You said buying a 'bunch' so im going to presume you plan a raid 5 type configuration probably with 4 or 5 of these drives. In that case I would definately go SCSI, instead of SATA. Scsi's performance is not really that big a difference until you hit multiple disks with simultaneous read/write spread across all drives (which is what raid 5, and 4 or 5 drives is going to do). Scsi will be probably as much as 50% faster in fact in that situation. (Main reason being that SCSI has a cpu on the card that off loads a lot of the work and can handle sequential across many drives at once at high speed, where as sata will put strain on your main cpu/IO buffers and is not well tuned to write to many drives at once). There are some newer SATA II cards that do a better job, but I haven't played with them.

If you just were doing 2 drives, I'd go SATA as the performance there should be about 10-15% at most on non stop intenstive usage (And if the box isn't pushing max usage 24 x 7 then sata should be almost identical).

As for 'what drive' stores the OS vs the database, if you are doing raid 5 it wont matter, but it really depends how you plan to string together 'this bunch of drives', i.e. Linux LVM software partitions? I'd go raid 5, and put the 'boot partition' on a non raid 5 partition to help on boot ups in case there is ever a problem.

[hostmaniac]

Thank you for that reply! Yes, I defenitely need a RAID setup and I was thinking a RAID 0+1 for the OS and a RAID 5 for the database drives. But you're saying with a RAID 5 it won't matter if the OS is on separate drives. How's that? Wouldn't that result in less seeks on the database drives? Especially since there will be lots of logging from Apache and the web site itself.

[turnkeyinternet]

In Raid 5, all drives 'merge' into 1. Every read/write is spread out across all drives already to balance it (and help on performance) . So in essence it wont matter, you cant specify on raid 5 "write my logs to drive 1, and database to drive 2". Raid 5 is just 'all of them'. It is possible to configure raid 5 to just use 4 of your 5 hard disks, and then install the OS on a seperate disk - would i suggest it? Not if i was putting 5 x 10k rpm drives in there, as you are wasting performance in my opinion. But i would put the boot partition on a non raid 5 (if i was using SOFTWARE raid), to make life easier in case trouble ever hits and corrupts things. But not the main OS and log folders, those could go in the raid 5 just fine.

[carguy84]

Last I checked, Raptor drives are just as expensive as SCSI 10k drives, no?

A DB on RAID5 will have write performance issues(noticable), fyi. The optimal DB setup would be RAID1 the OS, RAID1+0 the DB MDF and RAID1 the Log file. Install the DB executable on the OS drive, or it's own RAID1 if you have the space. Although if you have the space to put the DB executable on it's own RAID1, I'd use that space for the OS swap file, and still stick the DB EXE on the OS RAID.

Chip-

[RayWomack]

Originally Posted by carguy84

Last I checked, Raptor drives are just as expensive as SCSI 10k drives, no?

yes and 1/3 the performance and reliablity. SATA is a consumer item, SCSI is a comercial product.

[riverpast]

Originally Posted by PSFServers

yes and 1/3 the performance and reliablity. SATA is a consumer item, SCSI is a comercial product.

The Raptor SATA is essential the same as their SCSI drives except the interface. The reliability is rated the same.

Performance is for everyone to argue about.

[FHDave]

I would like to see where Raptor is rated as the same in reliability and performance then SCSI drives.

[krypttim]

we've used 16x74GB 10k RPM raptors with a 16port 3ware 9600 series cards and they sustain around 450-500mbps of throughput for file downloads etc.

no complaints here..

this is running on a 800FSB 3.06/2mb cache single cpu xeon NFS server. i find it that you need a quality controller.

while scsi is obviously "ideal" the cost per MB and for my application dont warrant the high cost.

[Yash-JH]

Yeah, I doubt Raptor SATA disks can match the reliability of a SCSI disk..

Also, don't forget, SATA uses your CPU as a controller. SCSI has its own controller. Heavy disk activity will put more load on the processors on a SATA system than on a SCSI system...

[tical]

Originally Posted by krypttim

we've used 16x74GB 10k RPM raptors with a 16port 3ware 9600 series cards and they sustain around 450-500mbps of throughput for file downloads etc.

That's not surprising at all. Because you mentioned 3ware, I'm assuming some sort of RAID. These cards are capable of upwards of 450-500 megabytes per second on reads, 8 times faster than the figure of 450-500 megabits per second. The manufacturer conservatively rates them at over 400 Mbytes/sec (see http://www.3ware.com/products/serial_ata9000.asp).

Performance-wise, 10k RPM raptors perform better than comparable SCSI drives on sustained reads, but they apparently suck on multiple simultaneous IO's. This review really tells the whole story.

As for reliability, I've never had any failures, but I know a few people who have. At first glance they certainly don't seem as reliable as a Seagate SCSI, but probably on par with the MTBF of a typical Quantum (Maxtor) Atlas or IBM (Hitachi) drive.

When building a RAID array, my money is on SATA Raptors, hands-down. Remember what RAID is - Redundant Array of INEXPENSIVE Disks. While the drives are not that much cheaper than SCSI, there's alot of value in integrated SATA RAID on most new motherboards, which typically don't cost much more than their non-RAID counterparts.

[riverpast]

The Raptor is rated MTBF at 1.2 million hours, same as SCSI drives. Look up the spec and you will see it. It uses the same mechanism as enterprise SCSI drives, except the interface. That's why it is so expensive comparing to regular SATA drives.

SATA drives will out-perform SCSI for sequencial read/write in large RAID, due to each drive has its own channel. SCSI would max the channel limit after 5 to 6 drives.

I would still use SCSI for DB. It is a lot of small random read/write and the bandwidth limit is not an issue.

[Yash-JH]

Your Raptor Drive is only priced $40 less than a Maxtor 10K SCSI Drive.. Given the falling prices of SCSI, I see no reason to go for SATA..

Also as clearly shown by that review, SCSIs will outperform any SATA drive in a server environment.. according to that review, by a whopping 65%.. That's huge IMHO. In a desktop environment, the Rapter drive outperforms a SCSI drive by a very small margin....

A desktop environment doesn't have too many simultaneous file reads/writes... as we all know. A server environment is going to have tons of simultaneous read/writes and that is where the SCSI's inbuilt controller gives it such a huge advantage

Spending a little more on SCSI disks means better performance and reduced server loads, as well as better disk reliability. We use SCSI RAID5 disk arrays for our servers and I honestly see it more economical to run than SATA or Raptor drives

[riverpast]

Not only the Raptor is not much cheaper than 10k SCSI's, the RAID card will end up more expensive than SCSI RAID. A good 2 channel SCSI RAID costs around $400, and support 24 drives. A good (3ware) 12 SATA RAID card cost $600 and only support 12 drives. I am comparing PCI-X to PCI-X.

[Erwin]

What do people make of this article?
http://www.pugetsystems.com/articles.php?id=19