Recommend me 2TB m.2 2280 drive for ZFS mirror, light VMs

[Kev]

I currently have a pair of 1TB 970 EVO Plus drives backed by a 100GB P4801x SLOG. I'm looking to upgrade to 2TB so I can get more snapshots in, lower utilization so fragmentation does not skyrocket. I'm, currently 76% allocated with 63% fragmentation. The workload will be light windows VMs running NVR and firewall, NAS, Dockers.

I'm looking for a pair of affordable 2280 NVME drives.

 

[EffrafaxOfWug]

I've been a happy user of Intel's reasonably priced P4101 drives for about a year (although I'm using mdadm as opposed to ZFS). I've been using two as an LVM cache and steady-state performance seems consistently good.

Is fragmentation a problem with using SSDs on ZFS? I'd have thought fragmentation would only be a significant problem with platter-based HDDs.

 

[Rand__]

Fragmentation due to the Copy-on-Write tech that ZFS is using which is impacting performance when not enough free large space slices are left to copy into

 

[gea]

Writing to an SSD/NVMe is only fast to an empty area otherwise you must read a whole page, erase the page and rewrite the page together with new data. Trim (only usable in low load conditions) helps to regain free areas. On high load conditions you need enterprise class SSD/NVMe as they do not suffer from a huge performance degration on higher fillrates like desktop SSD/NVMe do without trim.

Intel Optane is the only type of NVMe without this problem as they can access datablocks directly without the page restriction. Sadly they are expensive and not available with high capacity in M.2

Another item for serveruse is powerloss protection. Unlike regular disks with deactivated disk cache, there can be a dataloss on writes or garbage collection in a crash case. This is the second reason to avoid desktop SSD/NVMe in a server but hard to find with M.2. You mostly need the U.2 models that can be connected via an M.2 adapter cable.

For a first overview of 2TB M.2 models I use the filter options at Solid State Drives (SSD) mit Kapazität ab 1.92TB, Kapazität bis 2TB, Schnittstelle: M.2 (PCIe), Formfaktor: M.2 2280 Preisvergleich Geizhals Deutschland

Prefer the (datacenter) models from Intel, Micron, Samsung, WD etc. The cheaper ones are more read optimized, the upper price models offer better write values (write iops 4k and optionally low latency are the important values for VM storage) and endurance.