SSDs and Redundant Arrays

[peebee]

I'm new to SSDs. I understand the majority of their pros and cons but haven't dug into the details of the technology enough to answer my own question.

Is there a benefit in creating a redundant array with SSDs? We all know magnetic disks are prone to many physical woes that could cause drive failures and loss of data.

From a high level view of SSDs, you would think that they naturally negate most of the plaguing issues with magnetic storage. But, I don't know if they come with their own set of issues to replace those that they avoid.

Are SSDs unreliable enough to need redundancy in a casual environment?


I know, I know, it depends on how valuable my data is. 😉

Edit: By "casual" I mean something like My Documents redirection to a raid-5 storage medium, etc.

 

[Red Squirrel]

SSDs fail based on use, so yes, in fact you will probably want to have a raid with a semi used disk and a new one, at least. The failure rate of SSDs makes a typical raid almost useless as chances are they will all fail at once if the drives are bought new. Best bet may be raid 6 with a hot spare.

For any serious redundancy spindle drives in raid are still the best way to go, not to mention cheaper and more capacity.

either way make sure you have backups setup too, on a totally seperate storage system (external drive, tapes, or w/e - I prefer HDDs as they are cheaper per GB)

 

[MalVeauX]

Heya,

SSD's don't need redundancy, no more than a typical HDD in a casual machine needs redundancy.

The only time redundancy is important is when you have a ton of data in one place and you don't want to have to reload it or reaquire it depending on the nature of it. Important data is too risky to just have redundancy for, real backups are critical for important data so that's another issue entirely. But casual use, redundnacy is merely a way to ensure uptime on a set of data that may be rather large. When we're talking about data sets that only measures 500gigs or so, it's hardly a big deal to worry about since a complete mirror of that is entirely possible and cheap. It's only when we're talking several terabytes that you start to really want redundancy. The other place redundancy is good (regardless of size of data set) is simply to have an OS that is sitting in a redundant setup (like RAID1) so that there's no downtime or reinstallation when a drive fails.

SSD's setup in a RAID for redundancy is very much not worth it. It's too expensive for what you're getting.

You're better off having a SSD as your main system's primary disk, with the OS. Then have an HDD based storage medium (be it an array, or a non-raid method of redudent large capacity disks, like several large disks using Fbackup as synch/mirrors) separate from it that you can off load the data too, since data is not useful on a SSD (it's pointless).

For long term storage, SSD's are still not there yet. They have very long life spans and their own little issues. But they're too costly for their benefits for storage yet. HDD's are still the better option for longer term storing of data. SSD is only useful right now for speed of access, workstation and desktop use where lots of operations and reads are required for a smooth feel and speed. HDD is where you throw the big data slabs that are not accessed over and over the way a workstation access's its operating files.

Very best,

 

[peebee]

Thanks for the replies guys. I understand an array doesn't replace off-site backups whatsoever. I was more or less looking for an upgrade path once I out grow my 4x250gb raid-5 array. By the time I out grow it we'll probably be a year or so down the road but it did get me wondering about how reliable the technology is. And I'm sure it'll be more reliable in a year from now but probably still not worth the $/gb.

You both had good information and thanks for sharing.

 

[her209]

I thought I saw someone say that performance degrades on SSDs as it is filled. Is this true and is it also true for traditional drives?

 

[peebee]

I thought I saw someone say that performance degrades on SSDs as it is filled. Is this true and is it also true for traditional drives?

This is true for traditional magnet storage but I'm not entirely convinced it makes sense for SSDs.