‹ BackHN Continuity

Thread

The Tao of Backup

160 points · 55 comments · vntok

  1. throwaway81523 · · focus · HN ↗
    Haven't seen that in ages and thought it had moved. 20GB tape containing all the corporate goodies. That makes me smile.
    1. Joel_Mckay · · focus · HN ↗
      The $/TiB storage cost currently creates weird choices in backup media... even making some older media formats economical again. Just finished a consumer storage option survey yesterday.

      Even if you account for consumer drive+spare cost, a 8TB HDD is still the best JBOD option. For under several dozen 25GB projects, the BD-R disc drive is currently the cheapest media backup option (about 35% cheaper than HDD above 12TiB). Note 50G and 100G BD EOL media are actually equal to or a worse deal than HDD.

      Also, HPE LTO9 18GB Tapes are currently around 5 to 15 times cheaper than HDD and SSD in terms of data storage cost, but the fixed cost of tape auto-loaders and drives don't always make sense until you have a significant amount of backup data. Tapes may also create a single point of failure in use... so incremental backups are a non-zero risk, and triple redundant hardware is required (old hardware gets hard to find.)

      The classic joke is still true: "Fast, cheap, or good.. choose any two..."

      Best of luck =3

      1. Gigachad · · focus · HN ↗
        I looked in to the bluray thing and concluded it just doesn't make sense at any level. You have to buy a bluray writer which will become increasingly rare, and then you are limited to 25GB disks where you have to factor in a chunk of that will go unused as each project won't fit on exactly 25gb.

        For the effort you are expending, just getting a hard drive makes way more sense even if the $/gb is technically a little worse. The utility of hard drives is much better.

        1. Joel_Mckay · · focus · HN ↗
          >I looked in to the bluray thing and concluded it just doesn't make sense at any level.

          I mostly agree, but the 25GB M-Disc EOL media format is fairly interesting for archival purposes. The gamble actually made sense in this rare instance as each active project folder still fit on one disc, and the $120USD omnidrive firmware drives should keep the retro-equipment running for a few more years. These are relatively inexpensive even with a spare unit in the box.

          >just getting a hard drive makes way more sense

          In many cases this can be true, but the 3 years of HDD flight time compared to the 7+ year SSD wear life is also fairly close. It is weird, but the cost of higher capacity 18TB/24TB HDD also no longer make sense for JBOD either... unless you are hitting rack space constraints. =3

        2. computator · · focus · HN ↗
          Blu-ray, or any non-rewritable optical media, guarantees that it hasn't been tampered with. If I were attacked by malware, I like the confidence that the Blu-ray backup is absolutely guaranteed to be the same as on the date it was written. A hard disk used for backup might have been reattached to the network at some point after the initial backup and gotten infected/corrupted/altered.
          1. Terr_ · · focus · HN ↗
            > Blu-ray, or any non-rewritable optical media, guarantees that it hasn't been tampered with.

            In terms of external tampering, I think that need is better-served by encrypting everything, which you probably want to do anyway. Or at least using some sort of checksum signed by a key.

            However if the focus is "what if the backup process is compromised", then yes, having some date which is beyond its writing-reach may be useful. Another aspect of this might be a remote-backup system where one set of credential is enough for daily backups and restore, while another is needed in order to access a set of older duplicates that are remotely maintained as ransomware-protection.

          2. taneliv · · focus · HN ↗
            That depends on your threat model. If the attacker can swap the Blu-ray disc to a similar looking one, but with content they control, that absolute guarantee becomes moot.
      2. nxobject · · focus · HN ↗
        I've been down "LTO at home?" rabbit-hole... I nearly ended up buying a SAS HBA, until I realized that S3 Glacier is tape-as-a-service.
        1. Joel_Mckay · · focus · HN ↗
          AWS is an option up to 30TiB, but also feeds into the over-provisioned data-center market pressures. The recent "rclone --gui" solution does bestow rsync/sshfs like features for Windows users now, and remote mounts are easier/cleaner to bring up. =3
        2. sdcfgy · · focus · HN ↗
          S3 is too expensive to do a restore from. And you have to restore to verify.
          1. nxobject · · focus · HN ↗
            It isn't too expensive for my use case – per month, I retrieve about 500GB a month from Glacier Instant Retrieval to verify, which costs ~$15. Combined with other costs, my monthly bill is ~$50.

            I used to use Backblaze B2, which had cheaper egress at the cost of slightly more expensive storage (I think ~$5/TB/mo, with free egress up to 3x all current storage?) So I paid $20. But at some point AWS opened a datacenter near me, and I couldn't ignore how much faster data transfers got.

            1. sdcfgy · · focus · HN ↗
              It's ok when it's 0.5TB but we're at about 900TB.

              The point is the cost doesn't scale well.

          2. mrweasel · · focus · HN ↗
            Depending on the amount of data you have, might it not be less expensive than build the tape drive?
            1. sdcfgy · · focus · HN ↗
              I paid < $400 for my LTO5
              1. mrweasel · · focus · HN ↗
                I assume used. Sadly I'm not really in a market where that type of equipment is widely available second hand.
                1. sdcfgy · · focus · HN ↗
                  Yeah used with 1 year warranty.

                  Ah that sucks :(

            2. Joel_Mckay · · focus · HN ↗
              >Depending on the amount of data you have, might it not be less expensive than build the tape drive?

              Rule #25: Try to avoid making what one may purchase, as the total cost is often many times higher than first assumed.

              It is tempting for many, but often doesn't end well for businesses. =3

          3. smw · · focus · HN ↗
            use cloudflare's r2, no egress fees
        3. yread · · focus · HN ↗
          Just bought an LTO drive yesterday (after failing to cool its predecessor properly - dont be like me). They got more expensive more or less in line with HDDs :(
          1. Joel_Mckay · · focus · HN ↗
            Used Tape drives often had the write heads service hours go well past its recommended limits. Mission critical IT systems don't get "upgraded" off schedule very often. ymmv

            Anecdotally, I have seen Tape sets fail in production settings, as a remote office location admin was doing incremental backups... and the sick tape drive kept silently damaging each daily roll-back attempt. They may fail ungracefully in an archival context.

            I do not deny a janky BD-R drive option is situation specific, but for small projects I am fine with a 25GB disc $25.80/TiB solution with the occasional big file $62.42/TiB hit for 100G/128G EOL discs.

            HDD are less hassle, still hit below $34.63/TiB, and last a few years. Not a bad fall back option if you still have old inventory. =3

Open on Hacker News to reply ↗

Unofficial Hacker News client; not affiliated with Y Combinator.