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I think the moral of the story is; always use software RAID. Hardware RAID (even fake ones like Intel) are time bombs, either you have fun configurations like
by zaarn 8y ago
I think the moral of the story is; always use software RAID.
Hardware RAID (even fake ones like Intel) are time bombs, either you have fun configurations like this or the controller dies and no replacement exists.
Unless you'd absolutely need a HW RAID, I'd go for a Software RAID that mounts and works natively in Linux. I can put the harddrives into a fully foreign computer and it would work.
- ghaff 8y agoThe other moral is that RAID is not a backup. I’d also argue that for most individuals who don’t really need to worry about an hour or two of downtime, it’s a lot more useful to have good (multiple) current backups than potentially complex RAID configurations.
- anilakar 8y agoRAID is the zeroth-tier backup. At least it will prevent most of the horror stories where people accidentally destroy their backups when trying to restore them.
- arghwhat 8y agoNo. RAID allows you to combine make many highly fallible disks into one big less fallible disk. Making independent devices into a unified device is a concept that is the polar opposite to a backup. Your example is also why people say that two backups are needed. Once your live system fails, if you only had one backup, you are now left with none. What was a backup is now your only copy, leaving you very vulnerable.
- anilakar 8y agoI had this happen eleven years ago, when an integrated hardware RAID controller in a Dell server decided to literally blow up. Oddly enough, despite all the black burn marks on the mainboard, rest of the server seemed to work just okay. Another identical (hardware-wise) cold spare was already in the rack right below the unlucky one, but it wouldn't accept the transplant license dongle because of service tag mismatch. First I had to install Windows 95 just to run the service tag changer tool and flash the firmware on the spare controller to match the original before it recognized the old disks as an existing array. In around one week we were back up and running (this was a non-workplace environment so there were no concerned execs bugging us for status updates every fifteen minutes). Had we been using mdraid, we could just have inserted the disks in just about any commodity PC hardware. In hindsight, just restoring the week-old backups would have been easier. Lesson learned: even if you are using hardware RAID and have an ostensibly identical hardware spare available, it won't necessarily save you.
- majewsky 8y agoLesson learned: Backups don't count until you've actually tested your restore procedure.
- shifto 8y agoDepends on the use-case really. I use raid (if any) for performance reasons, so I prefer hardware raid with a nice controller and some lots of spindles where flash is not an option. I would never implement this with a software raid solution for reasons.
- tomatocracy 8y agoLikewise. If it’s not offline, verified and off-site, it’s not a backup. Raid is useful for availability as well as performance though. Also while we’re discussing raid, the price/gb of a mirrored set of larger disks vs a raid 5/6/10 of smaller disks (for the same total capacity) is always worth checking - usually comes out in favour of mirrored pair in my experience which also has better performance (especially when resilvering) and resilience and lower energy costs.
- guitarbill 8y agoseconded - storage is cheap, and with ZFS, mirrors can be grown, wheras arrays can't. i recently grew a mirror from 3 TB to 8 TB. strongly recommend using a three-way mirror though. don't be cheap.
- tivert 8y ago> Raid is useful for availability as well as performance though. Also for data integrity, with something like ZFS.
- deleted 8y ago[deleted]
- nikanj 8y agoIf anything, the moral of the story seems to be ”RAID is way too complex and dangerous for the benefits it brings”. For home desktops, that is. Server end is different.