derrick.l...@givex.com (Derrick Lobo) writes: >I have not had issues with the (sata) SSD either.... the nvme is really >slow for me its 6 ties slower doing basic operation like untaring a file.. >and im not sure if theres any config needed to make this work.
Here is some data from a cheap Samsung NVME card (about EUR100,- / 500GB). It's formatted as simple ffs, no logging with bsize = 32k, fsize = 4k. /dev/dk0 on /mnt type ffs (local) Reading from raw device gives about 2.3GB/s. % dd if=/dev/rdk0 bs=1024k count=10240 of=/dev/null 10240+0 records in 10240+0 records out 10737418240 bytes transferred in 4.489 secs (2391939906 bytes/sec) Writing a large file to the filesystem is about 1.2GB/s. % dd if=/dev/zero bs=1024k count=10240 of=testfile 10240+0 records in 10240+0 records out 10737418240 bytes transferred in 8.268 secs (1298671775 bytes/sec) Unpacking a tarfile with little files reads 23MB/s on average but the write load is of course much higher. % ls -l src.tar -rw-r--r-- 1 mlelstv staff 1582223360 May 15 00:31 src.tar % time tar xf src.tar 1.181u 24.089s 1:07.88 37.2% 0+0k 90+1578062io 0pf+0w While tar is running, iostat reveals it's writing at 381MB/s. device read KB/t r/s time MB/s write KB/t w/s time MB/s ld0 64.00 159 0.60 9.93 14.28 27350 0.60 381.29 dk0 64.00 159 0.63 9.93 14.28 27350 0.63 381.29 The difference between raw I/O and untaring a file is filesystem and virtual memory overhead. Taring it up again is of course much faster (read from cache, partially async write), but the destination is written at about 210MB/s. % time tar cf src2.tar src 0.529u 6.319s 0:07.11 96.0% 0+0k 0+40io 0pf+0w >From a freshly mounted filesystem you see the real I/O rates: % time tar cf src2.tar src 0.525u 7.476s 0:24.64 32.4% 0+0k 63369+49io 0pf+0w device read KB/t r/s time MB/s write KB/t w/s time MB/s ld0 6.34 17370 0.70 107.63 63.91 1008 0.70 62.90 dk0 6.34 17370 0.73 107.63 63.91 1008 0.73 62.90 Write rate is down to 62MB/s, even the total I/O is less than half of the in-cache case. This difference however is no software overhead, the CPU is sleeping Your system should show similar performance. However, your Intel NVME card is a bit older. The only guess I have is that it reaches its speed when you use multiple queues in parallel. But our driver currently only handles a single queue. -- -- Michael van Elst Internet: mlel...@serpens.de "A potential Snark may lurk in every tree."