Re: Intel 82576 Gigabit on Debian 7 slow speed.

[Dan Ritter <dsr@randomstring.org>]

On Fri, Dec 18, 2015 at 07:44:58PM +0200, Mimiko wrote:
> iperf -c ip
> ------------------------------------------------------------
> Client connecting to ip, TCP port 5001
> TCP window size: 23.5 KByte (default)
> ------------------------------------------------------------
> [  3] local ip port 36389 connected with ip port 5001
> [ ID] Interval       Transfer     Bandwidth
> [  3]  0.0-10.0 sec   835 MBytes   700 Mbits/sec
> 
> 70% of 1Gbit. Is this seems a problem with samba?

Do you have jumbo packet support on your switch and on all
possible clients? 5000 - 9000 byte ethernet packets can improve
raw throughput, at a (usually minor) cost in latency.

> dd if=/dev/zero of=test.bin bs=1M count=10000
> 10000+0 records in
> 10000+0 records out
> 10485760000 bytes (10 GB) copied, 24.5841 s, 427 MB/s

Looks normal.

> dd if=test.bin of=/dev/null bs=1M
> 10000+0 records in
> 10000+0 records out
> 10485760000 bytes (10 GB) copied, 2.24662 s, 4.7 GB/s

Pulled from cache.

> Disk is a zfs raid:
> zpool create -f -m none -o ashift=12 zfspool raidz2 .... (total 8 x
> 1TB + 8 x 2TB disk in SATA2 supermicro backplane)
> zfs set atime=off zfspool
> zfs set dedup=off zfspool
> zfs create -V 4T zfspool/backup
> zfs set compression=lz4 zfspool/backup
> mkfs.ext4 -b 4096 -q /dev/zvol/zfspool/backup
> 
> Is this samba problem or zfs problem?

RAIDZ2 is not a high-speed solution, it's a medium-safety
solution. Layering ext4 on top of ZFS blocks doesn't make
it faster, it just extends the reliability of ZFS to the 
ext4 fs.

Do you have a requirement for putting ext4 on top of ZFS blocks?
Can you use ZFS instead?


-dsr-