Hi, I'm having issues with write speeds to my unraid box...

 

To try to rule out computers, etc. I'm testing from 2 different computers:

 

PC1: AMD Athlon 64 X2 - 2Ghz processor / 2GB RAM / 1Gb Network Card

PC2: AMD Phenom II X4 - 3Ghz Processor / 4GB RAM / 1Gb Network Card

Unraid Box: Intel Celeron E3200 - 2.4Ghz processor / 2GB RAM / 1 Gb Network Card

Disks on all computers run at roughly 50-70 MB/s

Switch: Netgear 8port Gb switch

All connections wired

 

Background:

 

Some time ago I had this running fine, but then I

a) moved

b) had to replace the switch since it broke

 

Symptoms:

 

- Whenever you copy something FROM the unRAID box to any of the two PCs, write speeds are as expected between 40-70MB/s

- Whenever you copy something TO the unRAID box, you get an initial burst of mayb3 20MB/s, but then it quickly drops to an average of 10MB/s

 

Things I thought of:

 

- Network cables (tried replacing them, no change)

- Switch port (tried changing to another port, no change)

 

Additionally to those two items above, the thought would be that if the "Rx" pair of the port works fine (since I can read FROM the server at the right speed), even if the "Tx" pair was bad on either the port or the cable, well then switching them with either cable or port for the computer should show a difference, since I'd be using the pair that previously worked fine (albeit now writeing to the server would be fine but reading from it would be slow).

 

Don't know what else to try/check... Any suggestions??? 

 

Try writing to a disk share.

 

I had a similar issue (even writing internally) and it was a cache drive causing the issues.

Hmm... Don't have a cache drive. Right now my sistem has 5 1TB wd green drives (4 data, 1 parity).

 

How do I write to the disks directly? Would that be mapping the disk shares? Aything I can screw up doing that parity wise, or will it work just the same?

How "full" are your disks?  I've noticed slower writes when my disks start getting full (reads have always been fine).

 

Writing to disk share would be same as to the User share but you have disk#/ in front of the share

i.e. For user share Movies/Thor  the disk share could be disk1/Movies/Thor

The User Share will automatically recognize it also.

 

 

So, some disks are fuller than others. In the case of the one that is being written to now, it's only about 15-20% full  (attaching pic, it would be disk 4).

 

I just tried writing to the disk (i.e. share: \\Tower\disk4\TV Shows) with the same result, a very short initial burst of about 20MB/s to quickly fall back to about 10MB/s...

when writing to any user or disk share you are writing to the disk AND parity. Parity is the common denominator here, post a smart report for it and post syslog.