Readynas NVX extremely slow writes but extremely fast reads!
Hi there! I've a Readynas NVX which is behaving a little oddly of late. This specifically started when trying to set the network to use jumbo frames (something the rest of the devices on the network are happy with, at an MTU of 9000). The NVX is the only device who seems to take a thorough disliking to this configuration!
Summary:
NVX difficult to write to over CIFS (first attempt locks up, subsequent attempts succeed?!)
NVX very slow writes, very fast reads (EXCEPT when they are also very slow... inconsistent)
RAIDiator 4.2.27
1024MB DDR2 (5-5-5-24)
One ethernet connection
Disk write cache=on
Disable full data journaling = off
Optimise for OS X = off
Fast USB disk writes = on
CIFS file protocol enabled, all others disabled
Gigabit network (simple ZyXEL gigabit switch between PC and other devices: those being the NVX, a few other NAS boxes, and a HomePlug adapter linking downstairs where the router sits).
Replaced cables with new Cat6 cablage (just in case... seems it had no effect)
Other devices so far seem fine with high read/write rates on jumbo frames - this includes a tiny Open Media Vault NAS and an AsuStor AS-202TE, both of which have an MTU of 9000/jumbo frames enabled. OMV NAS runs as fast as its single SATA drive will allow, achieving vaguely 30-40MB/s r/w and the AS-202TE is more like 100+/70 r/w respectively.
Same NVX with jumbo frames off seemed to get fairly consistent 30MB/s writes/reads, and no difficulties starting transfers
Symptoms:
From a Windows 10 machine to the NVX via CIFS, I'll sometimes get blazing fast reads (100MB/s+) but writes are really slow (~25MB/s max, and it droops and fluctuates wildly between that and lower speeds, low as 1-4MB/s). I also find that on first connecting to the NVX, the first file I try to send just hangs and the operation must be cancelled. After that it starts transfers okay, but is slow as described. Generally reads end up slow as well.
What do you reckon? Bit of a head-scratcher for me!
Model: ReadyNASRNDX400E|ReadyNAS NVX Pioneer Chassis only
Re: Readynas NVX extremely slow writes but extremely fast reads!
Hi r00x,
You may also want to test it on your PC by directly connecting your NAS via LAN (ensure static IP address is set in order for you to access it). Also, which FW is running on your system?
Re: Readynas NVX extremely slow writes but extremely fast reads!
Hi there! Yes, I tested the MTU. It seemed okay up to 9000 (8972) before packets started needing to split.. Not sure what the problem is really. I've since backed the NVX back down to an MTU of 1500, yet I still get read rates of over 100MB/s and writes are still vaguely 20-30MB/s... so now I have no idea what's going on! It does seem to get rid of the problem where the first file write attempt fails/locks up though.
Could it be that it's just not that fast at writing? The disks are arranged in X-RAID2, if I recall? There's only three of them as well, as opposed to four. Perhaps the old x86 chip in this NAS just can't cope with a higher write speed than that on this array?
EDIT: forgot to add, I have also tried updating from RAIDiator 4.2.27 to 4.2.28, but it seems pretty consistent between the two versions.
