On Tue, Jan 30, 2018 at 03:29:41PM +0000, Terry Barnaby wrote: > On 30/01/18 15:09, J. Bruce Fields wrote: > > By comparison on my little home server (Fedora, ext4, a couple WD Black > > 1TB drives), with sync, that untar takes is 7:44, about 8ms/file. > Ok, that is far more reasonable, so something is up on my systems :) > What speed do you get with the server export set to async ? I tried just now and got 4m2s. The drives probably still have to do a seek or two per create, the difference now is that we don't have to wait for one create to start the next one, so the drives can work in parallel. So given that I'm striping across two drives, I *think* it makes sense that I'm getting about double the performance with the async export option. But that doesn't explain the difference between async and local performance (22s when I tried the same untar directly on the server, 25s when I included a final sync in the timing). And your numbers are a complete mystery. --b. > > > > What's the disk configuration and what filesystem is this? > Those tests above were to a single: SATA Western Digital Red 3TB, WDC > WD30EFRX-68EUZN0 using ext4. > Most of my tests have been to software RAID1 SATA disks, Western Digital Red > 2TB on one server and Western Digital RE4 2TB WDC WD2003FYYS-02W0B1 on > another quad core Xeon server all using ext4 and all having plenty of RAM. > All on stock Fedora27 (both server and client) updated to date. > > > > > > Is it really expected for NFS to be this bad these days with a reasonably > > > typical operation and are there no other tuning parameters that can help ? > > It's expected that the performance of single-threaded file creates will > > depend on latency, not bandwidth. > > > > I believe high-performance servers use battery backed write caches with > > storage behind them that can do lots of IOPS. > > > > (One thing I've been curious about is whether you could get better > > performance cheap on this kind of workload ext3/4 striped across a few > > drives and an external journal on SSD. But when I experimented with > > that a few years ago I found synchronous write latency wasn't much > > better. I didn't investigate why not, maybe that's just the way SSDs > > are.) > > > > --b. > > _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx
