On Wed, Feb 03, 2021 at 08:25:59AM +0100, BERTRAND Jo?l wrote: > Michael van Elst a ?crit?: > > On Tue, Feb 02, 2021 at 03:55:10PM +0100, BERTRAND Jo?l wrote: > >> Michael van Elst a ?crit?: > >>> joel.bertr...@systella.fr (=?UTF-8?Q?BERTRAND_Jo=c3=abl?=) writes: > >>> > >>>> But jumbo frames and Intel adapter don't increase NAS throughput : > >>>> 204Mb 407Mb 611Mb 814Mb > >>> > >>> Where does this information come from? > >> > >> iftop. > > > > But with what kind of disk operation? > > All operations : read, write, by dd or bacula-sd. If I understand, > bacula only writes sequential data files. Filesystem on this iSCSI > volume is ffs (v2) with log (and of course without sync or async options). > > > iSCSI naturally has a higher latency than a direct attached disk. > > To utilize a link you may need to generate more requests in parallel. > > > > For writing that's not that difficult as the client will buffer enough > > data. For reading you need large buffers or significant read-ahead to > > trigger concurrent I/O. > > > > You may also need to tune TCP/IP on the client. > > > > You could start a test with reading from the raw iSCSI volume > > with dd. You need a read buffer of at least 1MB to get the > > maximal concurrency. > > > >> [ ID] Interval Transfer Bitrate > >> [ 5] 0.00-10.00 sec 1.08 GBytes 931 Mbits/sec > > > > That looks reasonable for a Gigabit interface. > > Of course, but with dd, I only obtain : > > legendre# dd if=/dev/zero of=/opt/bacula/test.dd count=10 bs=10m > 10+0 records in > 10+0 records out > 104857600 bytes transferred in 0.537 secs (195265549 bytes/sec) > legendre# dd if=/dev/zero of=/opt/bacula/test.dd count=10 bs=100m > 10+0 records in > 10+0 records out > 1048576000 bytes transferred in 53.396 secs (19637725 bytes/sec) > legendre# dd if=/dev/zero of=/opt/bacula/test.dd count=10 bs=1000m > 10+0 records in > 10+0 records out > 10485760000 bytes transferred in 1026.927 secs (10210813 bytes/sec) > legendre#
How much RAM does this system have? I'm guessing you might be paging in those last two operations. Instead, try: dd if=/dev/zero of=/opt/bacula/test.dd count=100 bs=1m dd if=/dev/zero of=/opt/bacula/test.dd count=1000 bs=1m dd if=/dev/zero of=/opt/bacula/test.dd count=10000 bs=1m ie. keep block size down to a sane level. > 186 MB/s for the first file. 18,7 MB/s for the second one and about 10 > MB/s fort the third one. > > And I don't understand. If iSCSI target or raid6 subsystem on qNAP were > the bottleneck, CPU load should be greater than 1 and it's not the case. > Maybe I will try to add a SSD disk as cache (but I'm not sure that this > NAS supports cache over USB3). > > Best regards, > > JKB -- Paul Ripke "Great minds discuss ideas, average minds discuss events, small minds discuss people." -- Disputed: Often attributed to Eleanor Roosevelt. 1948.
