A copy should be acceptable for ZFS.
Good luck with your brain transplant operation!
If it fails, your last hope to recover some data from the failed pool would be to plug the remaining valid drives to a Windows computer (do not format the drives when prompted to do so!) and run Klennet ZFS Recovery. Scanning is free, and will report which files could be recovered by buying a license ($399).
A Disk Duplicator may be able to help, however the original drive must still be operational. Any software that would perform a sector by sector copy, which is what you would want in this case.
This is why we usually suggest RAIDZ2. Good luck with your recovery!
Not suitable for ZFS, i.e. data loss is to be expected. Not sure this is related to the issue at hand, but it should be replaced by a proper HBA with IT mode firmware asap.
This will be the next step, but for now I’m waiting to hear what the specialist has to say about the disk.
Thank you everyone for your help so far!
The good thing about the bad is that I was able to meet such a community.
I’m inclined to disagree. just as long as it’s in HBA passthrough…
myself I’m using a 78165 on my T340 server. I’ve seen and recommended them to others as well… they are a nice middle-ground between the 9200-9300 LSI HBAs once you factor in heat… and you get a huge convenience of both internal and external in one HBA.
I would be interested in knowing specific issues, if you have any…
Based on what information do you come to that conclusion?
If you search the forum (incl. the old one) you will find plenty of information on that topic.
TL;DR: A RAID adapter in HBA mode is something entirely(!) different from an HBA. And the fact that things work under normal circumstances says absolutely nothing about the suitability of a configuration. It is the worst-case scenario that matters. Here you run considerable risk, because the RAID adapter hides disk details from the OS/ZFS.
It turned out that the electronics are not faulty, but the surface of the disk, so only partial data backup is possible. I guess this doesn’t make much sense from the point of view of the raid array. It would be around $1,500 per disk anyway. So Klennet was left as a faint hope.
Klennet ZFS Recovery supports RAIDZ with one corrupt drives 
years of practical experience of my system and others. combined with knowing to exclude the generic copypasta of “it’s unsuitable buy LSI” type advice as basically all of it is unsubstantiated.
it does not, SMART works fine, 4kn works fine, hotswap works fine, expanders work fine (including in lsscsi)… it works like a normal HBA.
it is in LSI world, yes. but there is no second firmware for the adaptec cards. you set it yourself.
I’ve hosted a 528TB raw raidz2 pool on my 78165, I used it because this was a Xeon E3 server that was chronically low on PCIe.
the only complaint I had was the speed (hosting 56 drives on one HBA). that server is now a second server and hosts less drives, but I will maintain that it works fine, and there are no issues caused by the HBA itself. (and regarding 4kn, I rebuilt that ENTIRE zpool to be 4kn one resilver at a time via the WD HUGO tool, so… heavy load is fine)
Honestly I really want to start a thread on this because it is upsetting that the copypasta continues. it’s less of an issue now but when I bought the adaptec the LSI cards despite being just as old were generally twice the price for less ports, mostly because of this rhetoric.
Your experience is valuable, so please document it. However it’s fair to say that refurbished LSI 2008/2308/3008 are now cheap and plentiful enough that the basic advice will go on.
You have two failed drives… what about the other one?
If they are both online and have surface failures in different spots, then the data is still recoverable.
BTW, you can force dd to ignore io errors.
I guess we can agree to disagree.
Just a few comments:
Not quite, but it’s not the right thread for this kind of discussion.
I was only stating as such because I’ve seen it a lot over the years, in many places repeated many ways… and my intention wasn’t to belittle others??? where in my posts have I done so?
I have only tried explain that there is nuance here. I only wanted to share my real experience. and would be happy to learn if others have had experiences (good or bad) with this hardware but as I said, a lot of what is said about these cards is not from those who’ve used them which is a problem. my point wasn’t that it’s not the perfect ideal, but if the OP has to worry about cable/power/hdd issues with their system, that should be the priority IMO.
it really is a shame this conversation turned so sour… I guess there’s a lot of strong feelings here but that’s the internet for you.
Nah, words should be weighted. As a non native english speaker, I can say this can be difficult.
