Bob2

ouch. So I guess that's a pretty major flaw and something that the Synology does do. I'll have to re-consider my options. Perhaps I'll look at offline backups that aren't at risk of viruses or other wares.

That's good. Can unRAID detect & correct silent corruption (e.g. where a file goes bad over time and returns a different MD5 hash)? I'm not actually sure any RAID setup can do this at present.

Thanks so much. In that case it's looking like unRAID is probably the best option! Is it easy to schedule parity checks or does it require installing some extra plugin? I have had some HDDs in the past return faulty data without there actually being a read error / bad sector (such as files being corrupt over time etc.). I'm guessing unRAID cannot protect against this?

... so that means it CAN correct bad sectors but doesn't mean it regularly WILL correct bad sectors. Will it do anything regularly to detect & repair bad sectors or incorrect data? Like how synology does. Thanks

thanks. It sounds like a similar capacity to SH2 which is good. Is there support to prevent silent bitrot such as bad sectors? etc. like in synology where it scans regularly using BTRFS scrubbing? Will it email me when it detects a problem or it's time to change a drive?

I'm hoping unRAID has this by default (or a checkbox) so that I can avoid buying a synology as they're looking pricey & I already have a spare i7 computer and a load of old drives I'd love to set up as a NAS! I found this interesting article online about silent bitrot: https://louwrentius.com/scrub-your-nas-hard-drives-regularly-if-you-care-about-your-data.html It's an outdated article though, so I'm wondering if unRAID devs have now released an update to include regular BTRFS scrubbing? Thanks

I know it's an old topic but is there something that detects bitrot (of any type, including bad sectors), and fixes the lost data be rescuing it using the parity, on a regular basis on unRAID? I read there is something like this in synology so I'm hoping to not have to buy synology but instead self-build.

I'm trying to decide whether to go for FreeNAS self build, unraid self build or buy a synology. I have a lot of randomly sized hard drives. My data is very important to me, so I want at least 2 parity drives. I found a calculator for Synology, which tells me it'll give me 18.5tb of space with 2 parity drives under RAID array type "SH2". It also shows standard RAID 6 (with 2 parity drives) would only provide 4.5TB of space. Is there any similar raid type to SH2 with unraid? My spare hard drives (in TB): 2, 2, 3, 3, 2, 4, 0.5, 6, 2, 6, 1 Synology SH2 & RAID space calculator for random hard drive sizes: https://www.synology.com/en-uk/support/RAID_calculator?hdds=2 TB|2 TB|3 TB|3 TB|2 TB|6 TB|2 TB|6 TB|500 GB|1 TB|4 TB Also, is there a similar calculator for UNRAID with its supported raid types? The only one I could find was an old out-dated unraid calculator that was made in 2009 (!) by an unraid user and doesn't allow you to select the number of parity drives or raid type like the synology calculator. Old unraid calculator from 2009, probably out of date: http://unraid.category5.tv/ Would appreciate thoughts on this. Thanks in advance