100mbit dns-321 read speed issue - need guidance in collecting the right information to get help

[A K]

Hey there Alt-Fers,

I've been running RC3 on my dns-321, with a single 1TB drive, for few days now, and am looking for assistance with performance tuning.

Most of the posts here are about gigabit networks, and involve jumbo frames and the like, which don't apply to me on my lowly old 100mbps LAN.

The write speed to it is around 10-12 MB/s which I think is pretty good, and what I expected.  The read speed is less than 7MB/s, which is seems low, and is the same or worse than the old slow MyBook World Edition blue light unit I'm replacing.

I get similar speeds with Samba or FTP.

I'm guessing the above is not enough info to yield any clear answer (unless you experts tell me that <7MB/s is all I can expect) but I was hoping you could point me to the right kind of information and tests to do so I can post more helpful info.

Thanks!

ApK

[A K]

One additonal note,

I saw this 100mb/s benchmark for the stock firmware:

http://www.smallnetbuilder.com/nas/nas-reviews/30521-move-over-dns-323-d-link-dns-321-reviewed?showall=&start=3

Should I expect similar or better read speeds with Alt-f?   I'm testing on a WD red drive formatted Ext4.

Thanks in advance for any guidance!

ApK

[João Cardoso]

On Friday, September 6, 2013 3:26:36 PM UTC+1, A K wrote:

Hey there Alt-Fers,

I've been running RC3 on my dns-321, with a single 1TB drive, for few days now, and am looking for assistance with performance tuning.

Most of the posts here are about gigabit networks, and involve jumbo frames and the like, which don't apply to me on my lowly old 100mbps LAN.

The write speed to it is around 10-12 MB/s which I think is pretty good, and what I expected.  The read speed is less than 7MB/s, which is seems low,

Yes. Did you measure that on big (GB) files?

 I don't have a 321. Try the following:

As an aside note, I found that setting in /etc/samba/smb.conf
    socket options = IPTOS_LOWDELAY TCP_NODELAY SO_SNDBUF=87380 SO_RCVBUF=87380
increased my write speed a lot, from the default ~13MBps to ~18MBps 

 

Read speed was not altered, as SO_RCVBUF was not changed from the default.

 

and is the same or worse than the old slow MyBook World Edition blue light unit I'm replacing.

I get similar speeds with Samba or FTP.

Ah, disregard the above. If you have  low read speeds under ftp, it is not a samba issue

I'm guessing the above is not enough info to yield any clear answer (unless you experts tell me that <7MB/s is all I can expect) but I was hoping you could point me to the right kind of information and tests to do so I can post more helpful info.

From the forum posts you know that read/write speed is not high even on Gbps networks, and the 321 runs at about 80% the 323 clock speed... 

The DNS321 has 266 BogoMIPS

The DNS323 has 332 BogoMIPS

Thanks!

ApK

[A K]

On Friday, September 13, 2013 10:17:40 AM UTC-4, João Cardoso wrote:

Yes. Did you measure that on big (GB) files?

 

Yes, anything over 100MB or so seems to settle around the same speed.

 

Ah, disregard the above. If you have  low read speeds under ftp, it is not a samba issue

Rats, you got my hopes up there for sec.

From the forum posts you know that read/write speed is not high even on Gbps networks, and the 321 runs at about 80% the 323 clock speed... 

Yes, though I was hoping for closer to 8MB/s on read, like the benchmark result.  Doesn't seem right that it's the same as the MBWE, which by all accounts, should be slower.

Thanks,

ApK

 

[João Cardoso]

On Monday, September 16, 2013 6:37:08 PM UTC+1, A K wrote:

On Friday, September 13, 2013 10:17:40 AM UTC-4, João Cardoso wrote:

Yes. Did you measure that on big (GB) files?

 

Yes, anything over 100MB or so seems to settle around the same speed.

 

Ah, disregard the above. If you have  low read speeds under ftp, it is not a samba issue

Rats, you got my hopes up there for sec.

From the forum posts you know that read/write speed is not high even on Gbps networks, and the 321 runs at about 80% the 323 clock speed... 

Yes, though I was hoping for closer to 8MB/s on read, like the benchmark result.

The problem with benchmarks is that you have to reproduce all its tests conditions, and you can't do that.

In any case it is odd that you have such high write speed (near the possible maximum in the 100Mbps network) and low read speed.

For both samba and ftp there is the so called "window size", that affects throughput. As tuning ftp is simpler that samba, you could try to see if you can get higher read speeds with it first. You could also use one of the Alt-F network benchmarking packages: iperf, iptraf, netcat or netperf.

 

 Doesn't seem right that it's the same as the MBWE, which by all accounts, should be slower.

Don't know, can't talk about that

 

Thanks,

ApK

 

[A K]

The problem with benchmarks is that you have to reproduce all its tests conditions, and you can't do that.

Yup, understood.  Figured it was worth asking in case anyone knew of a setting or tweak that I might have missed.

In any case it is odd that you have such high write speed (near the possible maximum in the 100Mbps network) and low read speed.

For both samba and ftp there is the so called "window size", that affects throughput. As tuning ftp is simpler that samba, you could try to see if you can get higher read speeds with it first. You could also use one of the Alt-F network benchmarking packages: iperf, iptraf, netcat or netperf.

I might try, but I'm pretty satisfied as it is, and I really don't need another hobby.  ;-)

By the way, I overstated my write speed a bit.   It's consistent at 10.5 MB/sec, which is almost twice as fast as my old NAS, and very reasonable, I think.

It might be coincidence, but my sequential read speed seem slightly higher with RC4.   I usually saw 6.8 or 6.9, occasionally 7.0, but now I'm seeing a consistent 7.2.   You said elsewhere you did not performance-tweak RC4, so it may have nothing to do with it, but I'll take it.