Does btrfs met your requirements?
btrfs still has a write hole for RAID5/6 (the kind I primarily use) [0] and has since at least 2012.
For a filesystem to have a bug leading to dataloss unpatched for over 8 years is just plain unacceptable.
I've also had issues even without RAID, particularly after power outages. Not minor issues but "your filesystem is gone now, sorry" issues.
Pretty much all software-raid systems suffer from it unless they explicitly patch over it via journaling. Hardware raid gets away with it if it has battery backups, if they don't they suffer from exactly the same problem.
https://www.synology.com/en-global/knowledgebase/DSM/help/DS...
Their recovery documentation [0] indicates that SHR is just plain mdadm + LVM and a couple of NAS recovery sites [1,2] indicate the same.
In the end I got a Reddit post [3] with a response from a Synology representative who says that the btrfs filesystem will request a read from a redundant copy from mdadm in order to correct checksum errors.
I wonder whether this is unique to Synology or whether the change has been upstreamed into the main Linux kernel.
[0]: https://www.synology.com/en-global/knowledgebase/DSM/tutoria...
[1]: https://support.reclaime.com/kb/article/8-synology-shr-raid/
[2]: http://www.nas-recovery.com/kb_hybrydraid.php
[3]: https://www.reddit.com/r/DataHoarder/comments/5yb13m/anyone_...
I thought I wanted RAID5, but after reading horror stories of drives failing when replacing a failed drive, I decided it just wasn't worth the risk.
I currently run RAID1, and when I need more space, I'll double my drives and set up RAID10. I don't need most of the features of ZFS, so BTRFS works for me.
If a disk fails and resilvering causes a cascading failure, I can restore from a backup.
I think you might be mistaking RAID for a backup, which is a mistake. RAID is very much not a backup or any kind of substitute for a backup. A backup ensures durability and integrity of your data by providing an independent fallback should your primary storage fail. RAID ensures availability of your data by keeping your storage online when up to N disks fail.
RAID won't protect you from an accidental "rm -Rf /", ransomware or other malware, bugs in your software or many other common causes of data loss.
I might consider RAID10 if I were running a business-critical server where availability was paramount, or where I needed decent random read/write performance but even so I'd still want a hot-failover and a comprehensively tested backup strategy.
Redhat throwing towel on their support for development does not instill confidence either.
Nothing personally against Btrfs. Just an end user making a file system choice saying what I care about.
> People are making a bigger deal of this than it is. Since I left Red Hat in 2012 there hasn't been another engineer to pick up the work, and it is _a lot_ of work.