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In my environment SSD are either in RAID sets or mirrored like any traditional drive. This is just common practice, so a drive bricking itself while odd would n

In my environment SSD are either in RAID sets or mirrored like any traditional drive. This is just common practice, so a drive bricking itself while odd would not endanger the data. Our systems vendor is making a big push for SSD only systems for many reasons. Namely speed but the reduced costs for electricity and cooling are apparently significant too. There there is the form factor, they are going to be much more space efficient than spinning drives

deleted 12y ago
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jfindley 12y ago
It'd be interesting to see a real world test of this. I'm not sure how large the sample variation is with these units, but if you're actually hitting the write limits of your disks I don't think mirroring is going to be the most effective solution - as both disks are likely to start failing at roughly the same sort of time. Mirroring is really useful with spinning rust, where failures are (more or less) unpredictable and you need a spare to use while the first is replaced. I wonder if there's a better solution when the failure of the drive is more predictable that avoids having a second unit sitting there all the time - especially for applications where the data isn't absolutely critical.
falcolas 12y ago
> raid and > would not endanger data in the same train of thought does not compute. Raid arrays do not protect your data. Only backups will do that. In fact, striped raid arrays will tend to lose data faster than a drive by itself - when it comes time to calculate parity, they'll find an overlooked mistake and take out 2-3 more drives, writing off all the data on that cluster at once.
- rbanffy 12y ago
  The "R" in RAID is for "redundant". Unless we are talking about RAID-0, which should not even be called "RAID" (AID, perhaps?), it does, indeed, protect you from individual drive failure (how many and which drives can fail depends on the RAID configuration) and, therefore, the whole array will be, on average, more reliable than the least reliable of its component drives. There is, however, a lesson I learned - never, ever build an array with drives of the same maker, model and batch, as they will have a tendency to fail at the same time for the same reasons. I did not build the array (I'd never do it), but it failed under my watch. Luckily, the first drive to go went one week before the second and the third and I had a plan-B.

deleted 12y ago

[deleted]

jfindley 12y ago

It'd be interesting to see a real world test of this. I'm not sure how large the sample variation is with these units, but if you're actually hitting the write limits of your disks I don't think mirroring is going to be the most effective solution - as both disks are likely to start failing at roughly the same sort of time. Mirroring is really useful with spinning rust, where failures are (more or less) unpredictable and you need a spare to use while the first is replaced. I wonder if there's a better solution when the failure of the drive is more predictable that avoids having a second unit sitting there all the time - especially for applications where the data isn't absolutely critical.

falcolas 12y ago

> raid and > would not endanger data in the same train of thought does not compute. Raid arrays do not protect your data. Only backups will do that. In fact, striped raid arrays will tend to lose data faster than a drive by itself - when it comes time to calculate parity, they'll find an overlooked mistake and take out 2-3 more drives, writing off all the data on that cluster at once.

rbanffy 12y ago
The "R" in RAID is for "redundant". Unless we are talking about RAID-0, which should not even be called "RAID" (AID, perhaps?), it does, indeed, protect you from individual drive failure (how many and which drives can fail depends on the RAID configuration) and, therefore, the whole array will be, on average, more reliable than the least reliable of its component drives. There is, however, a lesson I learned - never, ever build an array with drives of the same maker, model and batch, as they will have a tendency to fail at the same time for the same reasons. I did not build the array (I'd never do it), but it failed under my watch. Luckily, the first drive to go went one week before the second and the third and I had a plan-B.