Quick info – LTO versus hard drives for archival

I wrote this up in reply to someone on the Facebook Post Chat group and thought I’d like to have it archived over here too. I will update it with more info a links soon:

Some comparisons and real world data for reference: LTO6 will run you about $1500-$3500 for the drive. $30-$60 per tape. Each tape can store 2.5TB. It’ll write at about 160/MB per second. We regularly use LTO5, tapes are about $20 for 1.5TB. On LTO5, we can backup, compare & verify a single 1.5TB volume in about 12-15 hours. Even with the 10-15% speed up to LTO6, I expect you’d see similar or slightly longer times to backup (with the bonus of an extra 1TB of archival). Media files don’t take much advantage of the compression of LTO, so look at the uncompressed numbers for planning. If you enjoy the command line, then you might be able to just use LTFS. If you aren’t a masochist, then you’ll be using Retrospect or Bru to do your backup and restores (make sure you make a plan to backup your backup catalogs!). Your media can be properly stored on a shelf for multiple years and should be readable until LTO7 drives are no longer readily available.

Bare Hard drives run about $50-$100 for 2TB. Transfer times vary depending on system capabilities, you could see times around 10 hours for 2TB of transfer (longer if you do a verify and compare afterwards). Your data can live on the shelf for a number of years but based on my experience I wouldn’t trust it much past 18 months. In my experience, hard drives fail far more regularly than LTO tapes become unreadable.

As with any archival system, you will want to put a procedure in place that allows effective and timely management of the media you want to archive. You have to make time in your schedule for project backups. Our LTO drive is attached to a separate system that is dedicated to that task and we transfer media into that system via a 10GB switch. You may find it works best to have a two-tier system: hard drives for short- or near-term archival and LTO for long-term storage. As always, YMMV.

2 Replies to “Quick info – LTO versus hard drives for archival”

  1. How about the HDD vs SSD factor? SSD prices are lower every day, transfer times faster. Not sure about long-term data integrity. Also, form factor is quite a bit smaller; makes storage space footprint smaller.

  2. Good point. SSDs *are* falling in price, but they haven’t quite reached the prices of HDDs or LTO…yet. HDD prices hover around $0.06/GB. LTO prices are around $0.04/GB. SSD prices are projected to go as low as $0.17/gigabyte (Computerworld). So, while they are getting better, it’s going to be a while before SSDs can replace HDDs or LTO on a price comparison. Sure they are faster, but backups typically are run overnight, so as long as we can stay within that 10-12 hour window, speed isn’t crucial.

    SSDs have an unknown shelf life simply because they haven’t been around that long. Brand new drives *could* last as long as 10 years. Drives that have passed their endurance rating (i.e.-number reads and writes over time), data retention rates could be as low as 1 year (Anandtech). Either way, SSDs are just too new and too expensive (comparatively) to be considered a viable option for long-term storage of media, in my opinion.

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