Heya everyone. I’ve got a Dell R740 that I’m experimenting with currently with Scale installed bare metal. It’s got a Cascade Lake CPU and I got myself a few 128GB Optane PMEMs to see how they would perform as storage.
I’ve never used PMEM before so I’m not certain what may be causing this, but two of my modules do not show a serial number. Because of this when trying to create pool using them I get a warning that two disks have non-unique serial numbers.
Any ideas why they wouldn’t show serials? As I said, not very familiar with using PMEM at all so maybe there’s something about how they were used previously that I’m missing, etc as it was all used hardware.
I believe the two that don’t show serials also appear to report as different sized disks. When looking in the bios I can see that there are two modules with 98% write endurance while the rest are at 100%. I am assuming this is part of the complication.
What happens if you temporarily remove all PMEMs except for the two without serial numbers?
Next, what happens if you then move those two to two of the now empty slots previously used by the working modules?
Ok yeah I’m picking up what you’re putting down here. Isolate if it’s the modules themselves or something outside of the modules. I can try a sanitize too, may as well see what happens!
I have seen the exact same setup with the exact same behavior, My server will only see 4 serial numbers. I have tested this with both 128GB and 256GB modules.
It also doesn’t matter if your running single or dual CPU’s it still only shows 4 serials.
I’ve tried updating firmware which made no difference. It seems odd to me that in both our cases it apparently cuts off after 4 serials. Is this be a TrueNAS issue? Known oddities with PMEM?
Running ipmctl show -a -dimm I am able to see a serial for each PMEM DIMM. Doesn’t really match up with the serials provided in TrueNAS though? Unless there’s some conversion of this format to something else as displayed in TrueNAS. Again I am not well versed in how any of this PMEM stuff works.
This is a manual for a Supermicro board, not Dell as far as I can tell. X12PSx would refer to motherboards like the “X12SPL-F” from SM which only has eight DIMM slots. Thus it would make sense that it only discussed up to four as that would be the maximum you could use in that board. That would also be for a different PMEM series as it’s an Ice Lake board if that even matters.
Here is the Dell documentation on 100 series PMEM:
