Designed for personal and home office NAS systems, our unique algorithm balances performance and reliability in NAS and RAID environments. WD Red™ drives are optimized for environments where idle time is available to perform necessary background operations. To ensure optimal performance, always check compatibility with your system. WD Red™ drives may not be suitable for higher workload environments. For ZFS file systems and overall NAS system compatibility, we highly recommend WD Red™ Plus drives, which are optimized for higher workloads.
I think that the explanation for the highlighted text is as follows (taken from Reddit):
Because then it has to write much data which potentially fills the CMR “cache” of the SMR drive. after the “cache” is filled the drive needs time to move data from CMR to the SMR part - and that’s where the problem starts. Additional writes are now really slow.
If you think it is bad now, wait until you need to resilver your array because a drive fails.
The reason that WD recommend the Red Plus (or Pro) drives is because they are CMR drives rather than SMR.
Also, if disk performance is important, use mirrors rather than RAIDZ1.
Not an expert on controllers but it was deemed unsuitable here:
You would need an HBA in it mode like an LSI. But I think you will not be able to fit the drives in your case then? Does it use a backplane? Maybe someone else has a recommendation here.
Way too expensive $ per GB wise. 8TB+ drives are much more efficient.
Even your nvme speeds are slow, are you copying from a single HDD?
SUMMARY: For a newcomer to TrueNAS ZFS-based storage, selecting trouble-free hardware can be a minefield if you don’t research it properly.
Even what would appear to be decent hardware from reputable manufacturers can be problematic:
Disk drives that are completely unsuitable for ZFS (or RAID in general) - because they are impossible to resilver.
Disk controllers that are incompatible with ZFS or need very specific configurations to be suitable
When to use mirrors vs. RAIDZx.
When to use L2ARC
When to use SLOG
How to configure SLOG when you use it (i.e. mirrors)
When to use a metadata vDev
How to configure a metadata vDev when you use it (i.e. mirrors)
P.S. @dan and I are trying to consolidate the accumulated wisdom of the TrueNAS community into Uncle Fester’s TrueNAS Beginner’s Guide (with full attribution) in the hope that there will be a single place for newcomers to go to get a comprehensive guide to planning, installing and running a small-ish TrueNAS server.
People will tell you, that you should avoid RAIDZ, because performance will probably suck, due to io amplification.
I for one think, that the more important part is that you won’t get a huge storage advantage over mirror.
You will not get the storage efficiency you think you will get in most cases. See this table.
For your 3 wide pool, you will actually get 66% (for the default volblocksize).
But that is only 16% more than 50%. Why bother with huge performance penalties, for such a small storage advantage?
