RAID

[katanaso]

just got a SSD for my OS, and I plan on backing it up to my HDDs. Before I do that however, I want to set up a RAID configuration. I am torn between RAID 1 or RAID 0, both offer what I want, but I dont have the money for 2 more HDD's to do a Raid 1+0 or a RAID 10. I have two Seagate HDDs: http://www.newegg.com/Product/Product.aspx?Item=N82E16822148433

Thoughts and tips?

To get back to your question, I'd go with RAID 1 if you don't need the full 2 TB of disk space.  You'll at least be safe from a single physical HDD failure this way.  RAID 0 will give you the full 2 TB of space, but it will also double your points of failure, as if either drive fails, the entire array is gone.

Backup your SSD to the RAID 1 HDDs with some type of tool.  I personally use Acronis to backup my system to the backup drives.

[MrRiplEy[H]]

Cheetah 15k 300gb SAS, $248.78 each (at Provantage) x 4 = $995.12 + Adaptec 6405 $314.99, subtotal $1,310.11 + tax and shipping = $1,454.92

Even so, any sata3 ssd in raid 1 will just wipe the floor with a 15k platter raid 10. Max IO per second at 4k is just off the charts compared to the platter drives. Only with cached burst data the traditional drives can compete at level terms, if the disk seek happens to hit cache that is

[2bighorn]

Even so, any sata3 ssd in raid 1 will just wipe the floor with a 15k platter raid 10.

Actually, it would be pretty close. SSD RAID1 (that is, SSD drives in RAID of comparable size, 2x600GB) would have advantage in sustained sequential read (maybe 10-20%), probably about even in 4KB random reads, 15k HDD RAID10 would still be faster when it comes to writes, that is sustained sequential writes and 4KB random writes. RAID10 with SAS drives would also be at least 25% cheaper.

Max IO per second at 4k is just off the charts compared to the platter drives. Only with cached burst data the traditional drives can compete at level terms, if the disk seek happens to hit cache that is

Nope, top of the line, synchronous mode MLC 512GB or bigger SSD are about the same at random 4KB reads (35K IOPS) and about 30% worse at random 4KB writes (25k IOPS) than good SAS 15k drive (about 35K IOPS 4KB random, both read and write).

You can get cheaper SSDs at about twice the 4KB random read/write IOPS, but they have trouble with compressed data (today, most of data formats are in compressed form), so real world usage IOPS would be much lower.

They are still ahead in sustained sequential read/write performance, more than double of a typical 15k SAS drive, but RAID10 would bring that to about equal level.

If I'd have to spend my own money, I'd choose 4 15k SAS drives in RAID10 over two SSDs in RAID1. In two/three years I'd probably go with SSDs though. But not today, not yet.

[Butcher]

I went with RAID-0 - the performance gained was beyond well worth it. I had toyed around without raid for a week then got it raided - there's a nice difference with Sata 3 drives 6G/second.

 I also added a SSD for my Intel chip to increase speeds, there was a measure of change to my system - about 10% gain from it. However I know you need an INTEL chip and board to run it.

my Drives are 2TB Western Digital's, and SSD is a 32gig patriot.

So far I am loving everything about the setup.

[MrRiplEy[H]]

Nope, top of the line, synchronous mode MLC 512GB or bigger SSD are about the same at random 4KB reads (35K IOPS) and about 30% worse at random 4KB writes (25k IOPS) than good SAS 15k drive (about 35K IOPS 4KB random, both read and write).

OCZ Vertex3 Max IOPS scores 85k so that's more than double your figures. Add in the factor that you can raid10 those ssds for the same money, you get a tough combination to beat. The Intel 910 is rated for 180k iops read and 75k write. The platters just can't cut the mustard anymore. Even the Marvell/Indilinx based SSD:s get 60k iops and that's with compressed data.

[guncrasher]

It's a good thing you didnt ask which type of ice cream is better.


semp

[2bighorn]

OCZ Vertex3 Max IOPS scores 85k so that's more than double your figures. Add in the factor that you can raid10 those ssds for the same money, you get a tough combination to beat. The Intel 910 is rated for 180k iops read and 75k write. The platters just can't cut the mustard anymore. Even the Marvell/Indilinx based SSD:s get 60k iops and that's with compressed data.

You don't give up, do you?

1.) We were comparing 600GB of useable storage, ie 4x300GB in RAID10 vs comparable in size SSD RAID1. 15k HDDs in RAID10 will be around 60k 4KB random read and write IOPS and over 300GB in sustained sequential read/write.
Now you can go and look for 512GB or bigger SSDs with similar performance because on board RAID1 won't improve read nor write performance. You may find one with better (on paper) specs, but not for much, and definitely, 2 SSDs of appropriate size won't be cheaper than 4 HDDs + controller.

2.) Use both HDD RAID10 and SSD RAID1 for a year, then benchmark it again. You'll lose some of the performance on HDD RAID due to fragmentation (fixable), but on SSD RAID you'll lose almost half of the performance.

3.) OCZ Vertex3 are really low end in SSD world. In real life scenarios IOPS aren't remotely close to those in benchmarks.

4.) OCZ Octane 512GB would be vastly better choice, but is also more expensive and IOPS aren't all that great, but they do better reflect the reality.

5.) Intel 910 has PCIe interface, not comparable with SATA, and 400GB model will cost you $2K and you're quoting 800GB model IOPS which is just few bucks short of $4K.
400GB 910 specs are: random 4KB - 90,000 IOPS read, 38,000 IOPS write (and I dare you to find the place where I can get them today)


Come back when you can actually configure 512-600GB SSD RAID1 with similar price, performance, quality and longevity as 600GB 15k SAS RAID10.

[MrRiplEy[H]]

You don't give up, do you?

1.) We were comparing 600GB of useable storage, ie 4x300GB in RAID10 vs comparable in size SSD RAID1. 15k HDDs in RAID10 will be around 60k 4KB random read and write IOPS and over 300GB in sustained sequential read/write.
Now you can go and look for 512GB or bigger SSDs with similar performance because on board RAID1 won't improve read nor write performance. You may find one with better (on paper) specs, but not for much, and definitely, 2 SSDs of appropriate size won't be cheaper than 4 HDDs + controller.

2.) Use both HDD RAID10 and SSD RAID1 for a year, then benchmark it again. You'll lose some of the performance on HDD RAID due to fragmentation (fixable), but on SSD RAID you'll lose almost half of the performance.

3.) OCZ Vertex3 are really low end in SSD world. In real life scenarios IOPS aren't remotely close to those in benchmarks.

4.) OCZ Octane 512GB would be vastly better choice, but is also more expensive and IOPS aren't all that great, but they do better reflect the reality.

5.) Intel 910 has PCIe interface, not comparable with SATA, and 400GB model will cost you $2K and you're quoting 800GB model IOPS which is just few bucks short of $4K.
400GB 910 specs are: random 4KB - 90,000 IOPS read, 38,000 IOPS write (and I dare you to find the place where I can get them today)


Come back when you can actually configure 512-600GB SSD RAID1 with similar price, performance, quality and longevity as 600GB 15k SAS RAID10.

Why stick to raid1? Who stops you from going raid10 on 300gig ssds? The ssd performance loss is a thing of the past, firmwares have evolved since then to handle garbage collection more effeciently.

I chose vertex3 because it's a common and relatively cheap drive. I don't know about you but I wouldn't want to have a raid10 worth of 15k scsi drives chattering away in my room. They're noisy as hell. Scsi drives are ok for servers but pretty horrible for a workstation.

[2bighorn]

Why stick to raid1? Who stops you from going raid10 on 300gig ssds?

$$, if you need a lot of storage, large and quality SSDs are still prohibitive in price. Not cost effective at all.

The ssd performance loss is a thing of the past, firmwares have evolved since then to handle garbage collection more effeciently.

I had OCZ Vertex3 240GB ($400 back then) in my main machine, upgraded firmware twice, after about six months of moderate usage (roughly 60% filled), performance is down by over 50% (measured with HDTune). Sequential read/writes got slower than my Seagate Constellation RAID1, and Constellations are relatively slow drives.
So, manufacturer numbers are definitely just for fresh drives and GC works to an extent only. Cut 50% and you get more realistic numbers. Still awesome performance, but too expensive if you need terabytes of storage.

The beef with SSDs is, that as they get better, price won't necessarily come down a lot, NAND efficiency (in terms of production) has limits.

I chose vertex3 because it's a common and relatively cheap drive. I don't know about you but I wouldn't want to have a raid10 worth of 15k scsi drives chattering away in my room. They're noisy as hell. Scsi drives are ok for servers but pretty horrible for a workstation.

Yeah, they can be loud, especially in a bunch, but they got quieter than they used to be. I wouldn't pick them because, while they're cheaper than SSDs, they're still too expensive for non-business use.

I went with hybrid solution. Replaced Vertex with 2x1TB 7.2k HDDs in RAID1 as boot volume. Slapped 24GB Intel SLC SSD in front as caching drive (IRST on Z68). Not as fast as SSD, but it's quick enough, reliable and cost effective.