5 ms·

What was actually ignored at that comparison is energy costs. Which can get quite somewhere, if you have all your disks running 24/7 and do not use power saving

by ktpsns 5y ago

What was actually ignored at that comparison is energy costs. Which can get quite somewhere, if you have all your disks running 24/7 and do not use power saving functions (which is frequently turned off in server contexts). Costs are in the ballpark of 5W per drive, given a contemprary 16TB drive this means 0.3W/TB, with 0.25EUR/kWh (a typical consumer price in Germany), this is roughly 0.6 EUR per TB per year. However, probably the replacement costs for these always-on disk drives will be even higher.

q3k 5y ago
Another consideration related to this is that tapes, being usually offline, as much more secured against accidental (or malicious!) erasure when compared to always-on hard drives. Also related is that tapes can easily be transported around/offsite, literally thrown in the back of a truck as they are. Try doing that to hard drives and see how many start throwing bad sectors after a round-trip.
- einpoklum 5y ago
  HDD's can be taken offline. But beyond that - if you're using HDDs as backup, you'll probably be using an HDD drawer, e.g. something like one of these: https://www.newegg.com/global/p/pl?d=hot+swap+hard+drive+bay https://www.newegg.com/global/p/pl?d=hot+swap+hard+drive+bay ... and the actual disks will usually be stored offline. So, no accidental erasure. But I agree that tapes are probably less sensitive to transportation.
archi42 5y ago
Tapes are offline and even require manual loading, so I think it's feasible to mitigate this by just powering down the backup system. At least that's what I do (with my primary NAS). But yeah, disk idle usage should not be underestimated. Also, some nit-picking: Energy prices in Germany are currently MUCH higher than that. We moved and had to get a new contract. Close to 40c/kWh. This makes your point a bit stronger. //edit: Also2, when doing the math I realized I should first transcode suitable content to h265 (per TB saved the necessary power is cheaper than a new disk), and as a second step replace my four or five remaining 1 TB HDDs with a single bigger drive to reduce the idle power draw (the NAS is on a btrfs mixed-size RAID1).
piaste 5y ago
If you want tape-like offline storage on HDDs, you can use a SATA docking station. Keep the 'active' backup drives plugged in, store full drives wherever you like. As a bonus, they can generally be used to offline clone drives.

by ktpsns 5y ago

q3k 5y ago

Another consideration related to this is that tapes, being usually offline, as much more secured against accidental (or malicious!) erasure when compared to always-on hard drives. Also related is that tapes can easily be transported around/offsite, literally thrown in the back of a truck as they are. Try doing that to hard drives and see how many start throwing bad sectors after a round-trip.

einpoklum 5y ago
HDD's can be taken offline. But beyond that - if you're using HDDs as backup, you'll probably be using an HDD drawer, e.g. something like one of these: https://www.newegg.com/global/p/pl?d=hot+swap+hard+drive+bay https://www.newegg.com/global/p/pl?d=hot+swap+hard+drive+bay ... and the actual disks will usually be stored offline. So, no accidental erasure. But I agree that tapes are probably less sensitive to transportation.

archi42 5y ago

Tapes are offline and even require manual loading, so I think it's feasible to mitigate this by just powering down the backup system. At least that's what I do (with my primary NAS). But yeah, disk idle usage should not be underestimated. Also, some nit-picking: Energy prices in Germany are currently MUCH higher than that. We moved and had to get a new contract. Close to 40c/kWh. This makes your point a bit stronger. //edit: Also2, when doing the math I realized I should first transcode suitable content to h265 (per TB saved the necessary power is cheaper than a new disk), and as a second step replace my four or five remaining 1 TB HDDs with a single bigger drive to reduce the idle power draw (the NAS is on a btrfs mixed-size RAID1).

piaste 5y ago

If you want tape-like offline storage on HDDs, you can use a SATA docking station. Keep the 'active' backup drives plugged in, store full drives wherever you like. As a bonus, they can generally be used to offline clone drives.