I have been using a Synology NAS (first, an 1812+, currently an 1813+) as a Veeam backup repository for about 5 years and was about to pull the trigger on the Synology DS3617xs until I saw last weeks' Veeam Community Forums Digest. If you aren't familiar with it, Anton Gostev (Vice President, Product Management at Veeam Software) sends a brief weekly message about things that mostly relate to Veeam, VMware and Hyper-V but also other things that he finds interesting. Anyway, he mentioned a QNAP data corruption issue and how low end NAS devices are not recommended. Excerpt here:
"Here's one more nail into the coffin of low end NAS usage > QNAP critical data corruption. Indeed, we had quite a few customers impacted by this issue – we just could not "separate" this particular one from a bunch of other issues causing corrupted backups with this sort of devices. As I keep repeating at my breakout sessions, usage of low end NAS is by far the number one reason of corrupt backups and failed recoveries that we're seeing in support. This is why for cheap backup targets, we've always been recommending using a physical Windows or Linux server with a bunch of disks instead."
He was referencing this - https://www.crn.com.au/news/qnap-keeps-quiet-on-critical-flaw-that-corrupts-data-468923
I started questioning this statement and found many posts by Veeam reps on SW that don't seem to have any qualms with them and in the SMB, Synology (also QNAP and ReadyNAS) are very popular for this use case. I have never experienced an issue with mine except I did have a drive fail when a larger than normal backup occurred and maxed the storage capacity. I replaced the drive and it rebuilt just fine. I am using OBR10 (not RAID5 like the QNAP article mentioned).
I also have external (separate from Veeam) tasks that run copies to an AWS S3 bucket to get the backups offsite almost immediately after the jobs finish. The only one I don't do that with is the "huge" file server, that is currently 2.4TB for a full backup. I also manually copy all backups to USB hard drives every weekday and take them offsite every weeknight. I do this because it would take quite awhile to download all the backups from S3 in the event of a disaster.
Should I reconsider my plan and start looking for an actual server to fill with local storage as my next backup repository?