It looks like I have one drive going/gone bad. The system put itself in degraded/read-only mode. Fair enough. (I was able to get a backup, but it seems that none of the TimeMachine backups are preserved.)
I inserted a new drive and after 20 hours the system was unhappy and back online. All good.
Then several hours later the offending disk had more errors. I took it out.
But the system is still in degraded/read-only mode.
I see elsewhere advice that I should have put the new drive in the old slot. But I didn't do that.
What do I do now?
How do I get the system back in working order? I've got plenty of disk space. I tried a scrub, and that wasn't enough to resync things.
How do I force a resync? Is that what I want to do?
- Malcolm
Model: RN31600|ReadyNAS 300 Series 6- Bay (Diskless)
Unfortunately, I believe what you are trying to do is not a re-sync, it's a shrink -- which the ReadyNAS does not support. When you add an additional drive with XRAID enabled, the volume normally will expand to one more drive. I believe yours did, even though one drive was failing. You are lucky that process didn't cause you to lose the volume completely. Now that the drive has totally failed, you are shy one drive for the new volume size to be redundant. I posted a very complex process using SSH and the Linux command line whereby a volume can be shrunk. Given you didn't know to replace the failed drive instead of add another, I'm going to assume that's beyond your level of comfort. That gives you two options: Replace the bad drive and re-sync with the new, larger volume; or backup, factory default, and restore. But given the current fragile nature of your volume, a current backup is a good idea even if you just plan to replace the bad drive. It's actually a good idea always.
OK, I was assuming the NAS was smarter than it was. (In retrospect, how was it to know that I was removing the failing drive permanently.) And that it mattered which physical slot it went into.
I'm ok with ssh, as I've been hacking Unix for many decades. I didn't find these directions online.
But it might be easier, as you point out, to just put a new drive in the failed (now empty) slot. Does it have to be the same model and size, or can it get bigger?
But it might be easier, as you point out, to just put a new drive in the failed (now empty) slot. Does it have to be the same model and size, or can it get bigger?
It can be bigger, with some constraints. When expanding the disk, it needs to match the size of another (larger) drive in the array, or it needs to be bigger than the largest drive.
But if it is bigger than the largest drive, then you won't see any capacity increase until you upgrade another drive to the same size. The capacity rule is "sum the disks and subtract the largest".
My procedure for reducing RAID size is here: Reducing-RAID-size-removing-drives-WITHOUT-DATA-LOSS-is-possible . It's not specific to your case, but it points the way. While many think XRAID is a proprietary structure, it's really "just" a set of algorithms that determine for you what the next step is in RAID expansion using standard Linux formats. I say "just" in quotes, because that's not an easy thing do do -- there are an endless number of possible situations. Thus, Netgear had to include some assumptions and limitations. One of the assumptions is that if you add a drive, you want to first add redundancy then expand an already redundant volume (except in the special case of a NAS with more than 6 bays). One of the limitations is they didn't even look at RAID reduction/re-organization.
I do think that a prompt asking if the assumed action is what is desired would help a lot, perhaps also giving the option to switch to FlexRAID if the answer is No. Many users mistakenly add a second drive to a 2-drive NAS thinking that will expand it, and finding out afterward that they now have a redundant RAID1 with no way to expand it with another drive. It is to those users that my reduction post is mostly aimed. You at least do have a bit of an option now, but you would have had more if you were warned ahead of time of the action that would occur and could abort it.
BTW, if you used the forum search to try to find the post, don't bother next time you need to search. This forum software has the worst search function I have ever encountered. Google will do a much better job.
