SSDs are getting better now, but are they as reliable as HDD? Can anyone shares his/her expertise on this?
The nice thing about them is that you know how many writes they should handle, and get a new one before some disaster happen. Sure, you can get a faulty unit, but you could get one with HDDs as well.
Instead, for HDDs, you couldn't be really sure. Yes, there's the "broken sector" count, but this isn't always reliable. Disaster could always happen randomly, without any warning before.
If you're interested in more stat, some sites are starting to run endurance tests [1][2][3][4], to see how much on average an SSD is supposed to last, and which brand is better.
Anyway, the only real solution is to run a raid, and keep frequent backups.
[1] http://techreport.com/review/24841/introducing-the-ssd-endur... / http://techreport.com/review/25320/the-ssd-endurance-experim...
[2] http://www.xtremesystems.org/forums/showthread.php?271063-SS...
[3] http://ssdendurancetest.com/
[4] "SSD Endurance test" on Google
A few are getting low on their media wear indicator (25% remaining) but they are getting replaced due to capacity issues.
Mechanical drives, on the other hand, are simply dead.
SSDs are fast - but you better back them up. When an SSD fails its usually complete and without warning.
Spinning drives will often give you some warning signs, clicking, slowing down, bad sector errors etc.
Spinning disks can be rebuilt with new heads or platter swapped into a new body.
With SSDs you cant just remove the NAND chips and recover the data either. SSDs use dynamic wear leveling to shuffle pages of blocks around - in other words - block 0 is not at block 0 -it could be anywhere... and if the internal map is lost - good luck.
The data in the NAND chips is also encrypted... they do this to ensure that erased sectors are actually erased. Because of the wear-leveling routine spies could possibly recover data from unused sectors - the encryption makes this impossible.
And for extra fun - intel likes to epoxy the chips to the board - just to be sure they don't fall off....
I compare them to a hover-car, with wheels you can get a flat and still make it off the freeway... but with the hover-car your just a sitting duck...
If you value your data, keep backups. And if you want to avoid hiccups in productivity, use RAID. Data that you don't have backed up is data that you don't have.
And keep in mind that RAID, while useful, is not a backup. It doesn't protect against theft, whole-computer destruction, human error, or many other things.
Not definitive, just a data point. (oh and the SSDs are the Intel X25-M (160G version))
I'm especially interested to hear from people who use many discs, and if they can share some information about the kind of use those discs get.
From what I've heard SSDs are more reliable that traditional spinning platter drives, unless you have a bad batch. This is especially true if there is more than one platter in the drive.
But I also recognise that it doesn't really matter. All drives fail, and no drive is reliable, so you assume the life is going to be 3 years and you have robust mirroring and backups and replacement policies.
A thousand times this. Over the last 2,5 decades I lost far more data than I’d like to admit. Floppy disks and CD-Rs that went bad, hard disks that failed, FTP services that were discontinued or corrupted data, etc.
My backup strategy right now:
* I have SSDs for use as system disks on all my computers. I keep track of their use and how long I’ve had them. Once one of them turns 3 years old, I’ll swap it out for a new one.
* Those computers are all connected to a Time Capsule (Time Machine) for incremental changes.
* Some files are also continually saved on iCloud (not all apps support it.)
* At night, a real backup gets run from the computers to a Drobo RAID setup.
* Everything of value (files I created) gets sent to Backblaze daily (an online backup service).
* For web projects, I also use a hosted subversion service.
* Most media I buy is cataloged by iTunes Match, where I can download it again whenever I need it.
* I use Dropbox, but not for backup, I use it to view files on the go and to share them with others.
I know my setup is not perfect, and I could use advice to improve it. I haven’t lost data in the last 3 years, but I’m keeping my fingers crossed.
I do count myself lucky to still have all my emails dating back to 1998 (but not the emails from 1994-1997). In large part, I have iCloud (née iTools, .mac, MobileMe) to thank for that.
On the other hand, the abstraction layer that lets a SSD be so reliable is complicated and it's possible for companies to screw up complicated things. There have been several instances of SSD firmware bugs that have caused data loss for users before they were fixed, so maybe be wary of new SSD models.
This is just one data point, I know, but I have never (knock on wood) had a hard drive of any kind fail before.