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Are Solid State Drives Worth the Money?

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Re: Are Solid State Drives Worth the Money?

#2
It really depends on the platform and requirements.

On a desktop, a three-drive RAID0 provides about the same performance, and gives you nearly 40x the storage for a given price-point.

On a mobile platform the physical space, vibration/motion, and power constraints coupled with the increased performance may make SSDs worthwhile.

Re: Are Solid State Drives Worth the Money?

#3
I'm spoiled by SSDs now. I've had an X25-M in my primary computer for almost a year now, and other computers feel so slow that I can't imagine going back. Even in servers, one X25-M can replace 4 15k RPM disks in RAID 10 for I/O load, not to mention the power savings.

Re: Are Solid State Drives Worth the Money?

#4

It really depends on the platform and requirements. On a desktop, a three-drive RAID0 provides about the same performance, and gives you nearly 40x the storage for a given price-point. On a mobile platform the physical space, vibration/motion, and power constraints coupled with the increased performance may make SSDs worthwhile.

On a desktop, a three-drive RAID0 provides about the same performance, and gives you nearly 40x the storage for a given price-point.

Quite a terrible idea unless you enjoy backup recovery sessions.

If the noise of 3 drives doesn't bother you then you can just as well get 4 and setup a RAID10, which is nearly as fast but much less likely to fail.

Re: Are Solid State Drives Worth the Money?

#6
post #4

It really depends on the platform and requirements. On a desktop, a three-drive RAID0 provides about the same performance, and gives you nearly 40x the storage for a given price-point. On a mobile platform the physical space, vibration/motion, and power constraints coupled with the increased performance may make SSDs worthwhile.

On a desktop, a three-drive RAID0 provides about the same performance, and gives you nearly 40x the storage for a given price-point. Quite a terrible idea unless you enjoy backup recovery sessions. If the noise of 3 drives doesn't bother you then you can just as well get 4 and setup a RAID10, which is nearly as fast but much less likely to fail.

I back up several times a day, automatically. I've run RAID arrays for years with no problems, but all drives eventually fail. An SSD is internally a RAID0 that can be up to 16 wide (that's how they get their performance). Used and managed properly (including proper backup and recovery), RAID0 works very well with good quality drives. If you have noise problems, then you likely have vibration issues that will shorten the life of your drives. I use anti-vibration mounts for all hard drives, and I hear my (quiet, anti-vibration mounted) fans more than I hear my drives. I also spin down the backup drives when they are not in use, so they add no additional noise.

Re: Are Solid State Drives Worth the Money?

#7
The Momentus XT seems to be a good compromise (4GB SSD that caches frequently used parts of a normal HD).

I know a couple of friends with them, and they say that applications load vastly faster, and their machines also boot faster.

It doesn't help with sustained throughput, but that's not normally a problem.

Re: Are Solid State Drives Worth the Money?

#8
post #4

Earlier quoted context omitted.

On a desktop, a three-drive RAID0 provides about the same performance, and gives you nearly 40x the storage for a given price-point. Quite a terrible idea unless you enjoy backup recovery sessions. If the noise of 3 drives doesn't bother you then you can just as well get 4 and setup a RAID10, which is nearly as fast but much less likely to fail.

I back up several times a day, automatically. I've run RAID arrays for years with no problems, but all drives eventually fail. An SSD is internally a RAID0 that can be up to 16 wide (that's how they get their performance). Used and managed properly (including proper backup and recovery), RAID0 works very well with good quality drives. If you have noise problems, then you likely have vibration issues that will shorten…

An SSD is internally a RAID0 that can be up to 16 wide (that's how they get their performance).

Erm. Actually they get their performance because they write to NAND instead of spinning platters. SSD controllers are also quite a bit smarter than plain RAID0.

RAID0 works very well with good quality drives.

A RAID0 over three disks has about 1/3 the MTBF of a single disk.

That can still be a worthwhile trade-off if you need the extra capacity, but if you're mostly after performance and reliability then a pair of SSDs, or even a single SSD, is the better choice.

Re: Are Solid State Drives Worth the Money?

#9
post #8

Earlier quoted context omitted.

I back up several times a day, automatically. I've run RAID arrays for years with no problems, but all drives eventually fail. An SSD is internally a RAID0 that can be up to 16 wide (that's how they get their performance). Used and managed properly (including proper backup and recovery), RAID0 works very well with good quality drives. If you have noise problems, then you likely have vibration issues that will shorten…

An SSD is internally a RAID0 that can be up to 16 wide (that's how they get their performance). Erm. Actually they get their performance because they write to NAND instead of spinning platters. SSD controllers are also quite a bit smarter than plain RAID0. RAID0 works very well with good quality drives. A RAID0 over three disks has about 1/3 the MTBF of a single disk. That can still be a worthwhile trade-off if you n…

You'll probably find this interesting reading on the internal architecture of SSDs:

     http://www.denali.com/wordpress/index.php/dmr/2010/02/02/ssd-interfaces-and-performance-effects
Also, while RAID0 reduces the MTBF, it's not linear. Drive life is not magically shortened as a result of the drive being in a RAID array (if you take care to isolate synchronous vibration). The life of the array is equal to the shortest drive life. In other words, if a drive would have failed after 25,000 hours in standalone operation, it will still fail in 25,000 hours in an array. The other drives may run to 100,000 hours, but it's a "weakest link" failure mode.

Re: Are Solid State Drives Worth the Money?

#10
post #8

Earlier quoted context omitted.

An SSD is internally a RAID0 that can be up to 16 wide (that's how they get their performance). Erm. Actually they get their performance because they write to NAND instead of spinning platters. SSD controllers are also quite a bit smarter than plain RAID0. RAID0 works very well with good quality drives. A RAID0 over three disks has about 1/3 the MTBF of a single disk. That can still be a worthwhile trade-off if you n…

You'll probably find this interesting reading on the internal architecture of SSDs: http://www.denali.com/wordpress/index.php/dmr/2010/02/02/ssd-interfaces-and-performance-effects Also, while RAID0 reduces the MTBF, it's not linear. Drive life is not magically shortened as a result of the drive being in a RAID array (if you take care to isolate synchronous vibration). The life of the array is equal to the shortest dr…

Also, while RAID0 reduces the MTBF, it's not linear.

Well, it is inverse proportional.

The life of the array is equal to the shortest drive life.

Erm. To be clear: Your risk of having a RAID0-set (over 3 disks) fail during a given timespan is 3 times higher than having a single-disk-"set" fail in the same timespan.

In other words, if a drive would have failed after 25,000 hours in standalone operation, it will still fail in 25,000 hours in an array.

That calculation makes no sense. If you have a single drive then that will fail, on average, after 25k hours. If you stripe over three of these drives then your array will, on average, fail after 8333 hours.

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