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i set-up the D-LINK DNS 323 NAS unit with RAID 1 (dual 2-terabyte 5400 rpm drives)
it works, but it is slow in copying files between my computer and it (8 minutes to copy 4.5 gig file between NAS and my PC).
i am using Cisco WRT160N router. replaced the network wires to the latest spec, and my computer has realtek PCIe GBE network adapter.
what are possible causes? i am not seeing anything particular in my router admin console or the NAS admin console..
Sonic Soul
Posted 2011-07-07T02:06:31.620
Reputation: 606
crap.. did't think a modern router would not be gigabit! that's crazy.. can you recommend some good routers? – Sonic Soul – 2011-07-07T02:26:05.283
check it where? PC? router? nas? what should the size be ? – Sonic Soul – 2011-07-07T02:31:12.457
If it's not that, then check your TCP packet size and windowing settings. Large files are not optimally transferred at most default MTU. My AirPort extreme works well at gigabit speeds, but you might find cheaper switches on Amazon if your router is fast enough for your wireless / internet uplink speeds. 4+ port Gigabit switches by D-Link and Cisco/Linksys run between $22 and $45 so you could wire up everything at higher local speeds. – bmike – 2011-07-07T02:31:50.927
1@Sonic Soul I know what you mean. I can't say that I have any specific ones in mind. I am usually a Netgear guy for home routers (for friends, etc.). I would just double-check when you replace it, or you could add a cheap gigabit switch that links to it, and then plug the NAS and PC's into that. I agree with your "that's crazy". It should be illegal to sell 100BT now. :) – KCotreau – 2011-07-07T02:32:48.507
It's hard to generalize - and the OS is generally going to discover the best MTU so unless you have ruled out everything else, it's not worth learning how TCP/IP works and realizing that the router and the PC and the NAS all need to work together at the same packet sizes. Also making your local network go to jumbo frames can cause extra load on the router when sending those large packets off the local network. See http://en.wikipedia.org/wiki/Jumbo_frame and http://support.microsoft.com/kb/949589 for netsh commands to reveal the current settings of MTU. 1500 is ideal, <1000 could be slow.
– bmike – 2011-07-07T02:42:09.4032@bmike Windows defaults to an MTU of 1500. That value also does not change on its own. If people start playing with their MTU, without understanding the effects, they are likely to have more problems. His problem has ZERO to do with MTU, it has to do with the speed of the integrated switch. – KCotreau – 2011-07-07T02:48:34.030
Phew - I've seen MTU discovery mess up on the low side, but my wording was BAD implying the default was wrong. On high end switches, I've loved MTU of 8-9K. That and link aggregation with fast SAN had me transferring this size file in something like 8 seconds. My apologies, you almost surely nailed this one from where I sit. – bmike – 2011-07-07T03:16:46.300
1@bmike Yes, on a SAN where the individual ports can be set, or they be VLAN'ed, or where the whole switch can be set...and when it is only traffic between one NIC and the switch. Being a home system, chances are, he does not have a second network card to go directly to the NAS, because he needs one that has an MTU of 1500 if he wants to go to the Internet, and home routers do not normally support such a high MTU. And in the end, it does not matter, 100BT is all you need to see to know that he will never achieve fast speeds. You sometimes have to temper the advice you give to non-pros. – KCotreau – 2011-07-07T03:24:12.017
Yeah, mtu has little if anything to do with his connection speed. Especially considering the router. Good work KCotreau. – surfasb – 2011-07-07T04:44:43.090
Bear in mind that the DNS-323 doesn't have a very powerful processor and so overall data transfer performance is not stellar - 12MB/Sec is typical: http://wiki.dns323.info/information:benchmarks
– Linker3000 – 2011-07-07T06:25:01.987