1

Background story: over time, I bought a lot of external hard drives. I got bored playing DJ with hard disks, and bought a Synology NAS (16TB JBOD, backed up to 8 external 2TB HDDs).

Skipping forward, I bought another NAS (32TB: 24TB RAID 5), and 5 external hard drives (4x4TB,1x8TB) as backup. My main machine holds 5TB backed up to a 5TB external drive, all my other computers together hold several TBs but basically all hold throwaway data.

All in all a total of 45TB, which is tedious to back up, not to mention it can be a lengthy process (all external drives are NTFS, which Synology does not handle all too well in terms of speed).

Given the fact that backuping up the NASses to HDD is also a risk (if disaster strikes during the backup, both could be affected), I wanted to add a step in between: a backup machine which continously backups up the 2 NAS devices and my computer, which in turn can be backed up to the stack of drives later on. This would automate the backup, and because all three stages are never active at once, disaster is avoided (yes, I'm a bit paranoid about data loss).

For the backup device I wanted to use an older computer with an SSD (OS drive) and 4x12TB or 5x10TB drives (not quite sure yet which one). Because not all drives are needed at the same time, I figured I could add a switch to each power connector to turn off the hard drive prior to booting the machine. That way only one backup drive would draw power, and only one backup drive could fail in case of (for example) a power failure. Of course the drive would never be turned on or off when the machine is running!

Now for the actual question(s):

  • is it possible to add a switch to each HDD molex? Physically there shouldn't be any reason not, but I'm wondering if disconnecting the power yet keeping the SATA connected could be an issue
  • are there any downsides to doing so? Besides the fact a HDD should never be powered up/down during the time the device is active, of course

I figure it would extend the life of the drive(s), not spinning it up and keep it running when it's not needed.

Any thoughts? Would Windows/Linux (not quite sure which yet) freak out on boot, noticing disks missing/changed/etc?

Thanks in advance!

Marlon

PS: yes nearly 50TB is a LOT of data, don't bother pointing it out :)

Marlon
  • 77
  • 2
  • 9
  • A lot of this depends on how you intend to set the system up... and you've not been very prescriptive. i.e: do you intend to use Windows or Linux? RAID? etc... Could you also clarify how much "_linear_" data you have? (excluding duplicates due to backups) – Attie Dec 03 '19 at 21:13
  • @Attie I don't know whether I'm going for WIndows 10 or a linux distro for this machine. I figure the OS shouldn't matter, since it should be a simple machine with either Windows and 4/5 NTFS drives, of linux and 4/5 EXT4 drives, no RAID. There will be no RAID, as I don't trust RAID for these large drives and rather prefer backups to RAID (I'm referring to the fact that a RAID-5 rebuild could theoretically not complete). What do you mean when you say linear data? I'm not familiar with that term. – Marlon Dec 03 '19 at 21:17
  • I'd strongly advise against using a filesystem like NTFS / ext4 for this amount of data, especially if the data is as important as you're suggesting... A filesystem that ensures the integrity of the file data is critical (like ZFS), and redundancy is incredibly beneficial as well... – Attie Dec 03 '19 at 21:59
  • @Attie ZFS could be an option, though I'm not familiar with the file system and would prefer Windows over linux because of the ease of use it brings. As for redundancy, the setup provides the redundance which a RAID would provide, without having the hassle of a RAID. – Marlon Dec 03 '19 at 22:02
  • SATA hot-plugging is built into the standard, but the design of the connectors is part of the standard: molex is not part of the standard as the plug pins are sized to ensure ground first, then power, then data. Presumably one (with sufficient knowledge of the domain) can have multliple switches to simulate the ordering: https://superuser.com/questions/925847/desmistifiying-sata-hotplug – Yorik Dec 03 '19 at 22:19
  • @Attie To elaborate a bit on the ZFS part: I tried FreeNAS and while the setup was easy enough, I couldn't even get a simple share to work (I could never get access from my Windows machine to the share). I expected the simplicity of a Synology but gave up on FreeNAS after this (perhaps too soon). I could always go for a third NAS with 50TB in RAID5, but I'd rather not pay for a NAS device that would be useless, as this would be a backup box without further purpose. – Marlon Dec 03 '19 at 22:19
  • @Yorik thanks, but I'm not looking to unplug the SATA cable physically or via a switch, only the power cable. The SATA cable will always remain plugged in. – Marlon Dec 03 '19 at 22:23
  • the point is that there is an order to the process, and if you mimic the process, you are probably in-spec. I assume leaving the data line(s) connected is acceptable, but it should be researched. – Yorik Dec 03 '19 at 22:38
  • The point I'm trying to make is that NTFS does not provide _any_ level of assurance about the file contents, and even a single disk ZFS pool is only able to detect errors (not attempt to correct them). I'm sorry to say it, but unless you already have a very laborious process in place to index and verify the contents of your files, I'd expect you to have some level of data degradation already - the data I've been keeping around for years certainly does. If you are concerned about the integrity of your data, you should seriously consider something like ZFS. – Attie Dec 03 '19 at 22:49
  • ... configuring samba so that Windows clients can access the files is trivial. – Attie Dec 03 '19 at 22:50
  • I know I'm not answering your question about "_switching the power to hard disks_", but I really don't think that is a sensible proposal in the scheme of things... there are other things you can do to protect your data that will be _**much**_ more beneficial. – Attie Dec 03 '19 at 22:52
  • 1
    @Attie It may not be a direct answer, but it's given me a lot to think about, so thank you anyway! – Marlon Dec 04 '19 at 20:58

0 Answers0