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I've used Dell Perc RAID controllers in the past. In those systems, the (hardware) RAID controller usually has an onboard battery backup system that stores the cache state in the event of a sudden power interruption. This is critical to prevent file system corruption.

Our organization is now getting Synology DS36xx NAS boxes, and I'm trying to figure out if there is an equivalent battery backup technology for the RAID those systems use. Is there? Or if not, is there something about the way their RAID works that guards against corruption from sudden power failures?

(Note: yes, we're putting the NAS systems on UPS battery backup. But batteries only last for a limited time, and there is always the risk of failure even with a UPS.)

mhucka
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    afaik no, because of that most of the device using software raid, so usually the answer would be no. But you can usually also connect to the ups via data link and let the NAS shutdown when the ups gets critical – djdomi Jun 25 '22 at 07:40
  • @djdomi I agree, it's crucial to connect the UPS data signal and make the NAS perform an orderly shutdown. There's still a risk of failure with such a scheme. So, I'm trying to understand how robust these NAS systems are, independently of other arrangements. – mhucka Jun 25 '22 at 15:13
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    well, that would lead to a opinion based answers. I could speak only for about the customer we serve and they are usually very good at this point. however it also depends on what raid level, what kind of filesystem is being used and a lot more factors. as always a zero trust is always a good decision and create 2 backup for the same target may ve more secure but even more expensive – djdomi Jun 26 '22 at 10:20
  • @djdomi I tried to make my question specific enough that it admits of an objective answer, precisely to avoid opinion-based answers. If I failed somehow, please let me know how I can improve it. – mhucka Jun 26 '22 at 15:40

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Those NASes don't use any battery backup for their cache.

Seconding djdomi's comment: They basically use software RAID and the main memory used as cache isn't backed up. So, make sure you hook them up to a UPS at all times if you're concerned about your data (use a data link or SNMP for safe NAS shutdown on power failure). A slightly better NAS has redundant power, so it doesn't fail when the UPS does. You can either use two UPSs or connect one PSU directly to mains.

Hardware RAID like PERC is another class. If you're looking for that in a box you'd need an entry-level storage array like Dell PowerVault or HPE MSA to start with (they're storage only, no NAS features though).

Zac67
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  • I would suggest that you take my comment as a reference , because it feels a bit like stealing the answers from my side ;) – djdomi Jun 26 '22 at 10:22
  • @djdomi Sorry, didn't mean to - I started out with that they use software RAID and the rest came naturally. ;-) – Zac67 Jun 26 '22 at 10:27