How long does data last on an SSD with no power?

[BLinux]

$100/TB is worse than using HDD for backup.

the cheapest considering the cost of drives is BD-R. but not exactly the most convenient if you have to keep swapping discs so you cant do huge unattended back up.

yes, it is worse than HDD for backup in terms of $/TB, but it is more durable than HDD too. Depends on what you value more and what your priorities are. I wouldn't use optical media for any type of non-archival backup; I think magnetic is the best choice there. But for archival data, data that I know is not going to change, I think there's a case for BD-XL. The $/TB is lower if you use 50GB or 25GB BD-R.. so if your data set is smaller, and you care more about $/TB, and it's archival data, then 25GB/50GB BD-R might be a better choice. Having to swap discs is a pain, but again, if it is archival data, you only do it once in a while.

 

[EffrafaxOfWug]

I feel we've strayed from the topic somewhat, but it has reminded me that I've got an OCZ Agility 120GB in a box somewhere that's been unpowered for about 5 years now - must dig it out and see what sort of a state it's in.

For all the spiel I've seen about archival-quality optical media, I'm not buying it - having been repeatedly burnt by crappy CDRs, crappy DVDRs and crappy archival-quality DVDRs, I don't want to be a canary in the coal mine for optical media. If I was going to back up to something that is slow*, I would use tape; an LTO5 holds 30x what a 50GB BDR might, and support for tape drives in backup software is far superior to that of optical media in my experience. Brand new tapes at £20 each vs. ~7x50GB BDRs at £20 each means that as soon as your backup footprint - archival or otherwise - exceeds a few TB, then you're better off going with tape. Take into consideration the number of times you'd have to change the optical discs vs. the number of times needed to change tapes and it becomes a no-brainer.

Personally, I use the ol' periodic rsync+hardlink to portable hard drives (mostly those cheap 2.5" 4TB seagates now) which are then scurried away offsite, gets me infinite incrementals and a complete restore of a particular day is a one-liner.

* Optical media I have difficulty getting more than 15MB/s out of BD-media, tape will usually happily stream at 100MB/s or more.

 

[Bob T Penguin]

@EffrafaxOfWug yes...things have strayed a bit off toopic. Your use of external 4TB hard disks is what I was thinking about, but using SSD's because they have more "shock absorbing" capability. I have less than 1TB of data i need to back up off site, so the cost / GB number doesn't bother me. I suppose I could use a cloud provider, but I don't use MS or Apple OSs.
Regards
Bob

 

[EffrafaxOfWug]

"Cloud" just means "a server somewhere" Pretty sure there are cloud vendors that support linux natively, but as long as you've got upload bandwidth to keep pace with the deltas, there shouldn't be any difference between J Random Cloud Vendor and J Random Server. I have a (linux) server at a mates house that keeps a versioned copy of my files, plus I keep offsites in the form of the portable hard drives.

If your dataset is <1TB and relatively static, no reason not to put it on SSD if that's within budget - should* be good for at least a couple of years, but for the same budget you could also buy a bevvy of 2TB platter-based drives and keep multiple offsites (one at work, one at your parents', that sort of thing) and cycle them - as long as you're reasonably careful, shock shouldn't be an issue. I call this Redundant Hodge-Podge of Offsite Cheap USB Backup External Drives, or RHOPOO-CUBED for short. I've got udev rules that kick off the backup script as soon as the backup drives are plugged in, and a cron that fires off reminder emails to bring in, say, RHOPOO-CUBED #4 if it senses it hasn't been backed up for a while.

If you're going to mail or courier them to a secure vault in an old salt mine, then you could go SSD to eliminate the shocks, but IMHO money's better spent on some closed-cell foam blocks as these would come in handy for handing regular drives out to relatives as well.

The most reliable way of testing the viability of your backups is doing a test restore every so often - a backup where you haven't tested the restore is only a potential backup and there's nothing worse than the false sense of security of thinking you've got a backup. Here portable HDDs have a distinct advantage over optical and tape (depending on your backup method) that if you're doing file-based backups then you can generally just plug the drive in and clickety a few files - epitome of the KISS philosophy really.

* Canary-time again

 

[BLinux]

@EffrafaxOfWug yes...things have strayed a bit off toopic. Your use of external 4TB hard disks is what I was thinking about, but using SSD's because they have more "shock absorbing" capability. I have less than 1TB of data i need to back up off site, so the cost / GB number doesn't bother me. I suppose I could use a cloud provider, but I don't use MS or Apple OSs.
Regards
Bob

I don't use MS or Apple OSes myself, and I've had good experiences with CrashPlan thus far, except for their upload speeds, which has gotten a bit better over time. But for 1TB of data, it should be fine... I am doing 6+ TB and that's going to take a while. 1TB went up to their cloud in about a 2 months.

I would not rely on any single source as your sole backup; have multiple strategies - for me, I have external USB drives, cloud, and optical. If prices on any recent tape drives would come down further, I might consider that too.