Will Newegg not ship internationally? Or do not give the cheap pricing? If it's still economical I can sell you one at cost (plus shipping) if you'd like.
Optane P1600X 58GB $40
- Thread starter altano
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You can configure zfs as far as I know as to how often it should flush.
And if you put this drive in front of a Spinning pool/SSD pool that have a higher sustained sequential write speed than 890 MB/s - it will slow you down. Obviously if you have random sync writes the picture is different - but for sequential writes - this is a slow drive.
I only ever mentioned sequential write speeds - and if you have a pool that can sustain 10GB/s sequential write speed - you are being slowed down. Scroll up and read what I wrote about pool speeds.
So again - if you have a pool that is faster than 890MB/S when doing sequential writes (sync) - you will be slowed down by adding this "slow" drive as a SLOG.
For latency and IOPS its a good idea to add a drive like this, but if you care about sequential write speed, i.e. if you are doing video editing or similar where you write massive amounts of data sequentially you will be dissapointed. (If you have a pool that is fast enough sequentially)
Also - why even mention this? Do you put a SLOG in front of a single SSD? I guarantee you that putting together a pool with SSD's can be much faster both random and sequential than the optane drive. IOPS might be better with a optane in front, but you will suffer sequentially.
Depending on your risk tolerance and hardware capabilities you can pool multiple SLOGs, which will increase bandwidth. I've done this before with the old Sun F40s (4 x 48GB MLC) and NVDIMMs. Worked as expected.Just remember - these drives are very slow for a NVME.
IOPS are awesome, but their sequential bandwith are like a 3rd of a normal m.2 SSD.
Intel® Optane™ SSD P1600X Series (58GB, M.2 80mm PCIe 3.0 x4, 3D XPoint™) - Product Specifications | Intel
Intel® Optane™ SSD P1600X Series (58GB, M.2 80mm PCIe 3.0 x4, 3D XPoint™) quick reference with specifications, features, and technologies.www.intel.com
So if you have a ZFS pool backed by spinners, where total sequential write speed is less than 1GB/s you are golden - anything higher - you need a better SLOG or it will slow you down.
Riley
Yes SLOG VDEV's follows the same rules as other vdevs - but I am not sure if you could build a striped mirror, or if you are limited to a single level of devices. You probably are.
SLOG (Seperate Intent Log) is a special VDEV that replaces ZIL (ZFS Intent Log) writes to the main VDEVs.
ASync writes go to RAM then the pool in transaction groups, they don't hit ZIL/SLOG.
Sync writes are committed to ZIL/SLOG before being committed to primary VDEVs in transaction groups.
If you put SLOG in front of spinners where media endurance isn't as limited then you primarily stop the write heads from thrashing back and forth between ZIL and DATA blocks. Writing data to ZIL and then again to the pool may not be concerning from a media endurance POV but if you're seeing x MB/s sustained the disks are seeing 2x MB/s bandwidth consumption.
If your pool is flash ZIL latency/random RW seek contention isn't crippling like it is to spinners, here SLOG mostly prevents you from halving your useable endurance by writing all SYNC data to the main VDEVs twice, but your SLOG should be faster than the pool which for modern SSDs is difficult without multiple SLOG VDEVs. An advantage to Optane here besides endurance is that it's not buffered so instantly committed and the sustained write speeds span entire volume, you don't need an Optane SLOG to match the DRAM cache speed of your SSDs only the bandwidth they can deliver after the DRAM buffer is saturated.
rms-200 is also an awesome - albeit hot running beast of a slog. I've got a couple of those and use them as SLOG for optane pools!I had a similar experience with radian rms-200
Found a bunch of them on ebay for like 80 or 90€ each (free shipping in eu made them an awesome deal here)
Probably not but you can certainly test it. I benchmarked using Optane for a slog and it makes sync writes almost as fast as async writes: about 10% slower.
A faster slog likely wouldn’t improve perf.