DSM-G600, DNS-3xx and NSA-220 Hack Forum

Arcain · 2011-02-22 13:31:22

Hi,

I'm using my DNS since 3 years or so now, running 1.08 firmware atm (with ffp), and it worked fine for most of the time with my WDC WD7500AAKS-00RBA drive. It's connected to gigabit switch and works in that mode. Since i rarely upload anything on the NAS and use it mostly to read stuff i never really faced the problem, but recently i had to upload few gigabates nad noticed that it's going up to 1MB/s only. I'm sure it was around 8-10MB/s in the past. It's the same when transfering using Samba, FTP and NFS, tested on few computers, even connected directly with PC. Same problem occurs when tried to download a file to NAS directy (using telnet console and wget) or even when writing to disk directly (dd if=/dev/zero of=/mnt/HD_a2/output.img bs=8k count=256k). Device also locks up when writing to disk, waiting for any command output (ls, top etc...) takes even more than a minute. Downloading from the device is fine, with 15MB/s speed, doesn't lock device at all. Once i upload a file with that low speed i can then read it back with full speed again so most likely it's not bad blocks issue here.

I'm preety sure it's not network problems, iperf with NAS as server hits over 130Mb/s, as client around 300Mb/s. hdparm and smart says that hdd is fine with cached read at about 28MB/s. The only problem is with writing. I already run fsck on the drive, installed cleanboot and there's no warning about mounting unclean filesystem anymore. Also, e2fsck never found any error during check. I also tried latest alt-f as firmware with same effect. I also recenly converted FS from ext2 to ext3.

Any idea what can be wrong and how to get it back to normal work with possible no data loss on the drive?

Last edited by Arcain (2011-02-22 13:39:31)

InBonobo · 2011-02-22 15:40:48

I can think of 3 possible issues:
1. I've had an "advanced formatting" large capacity green WD and it behaved similarly. Look into your drive's specs, if that's the situation, I wrote a guide on how to use it, but it's probably better not to use it in a NAS - it's not made for that.
2. Your drive shipped with some jumper inhibiting performance - but this, as the previous possibility, does not explain why it worked fine before (could it be that you did not notice?)
3. Your drive is failing. All good things come to an end. Incidentally, this is the only answer consistent with earlier normal behaviour.

Arcain · 2011-02-22 16:16:50

1. I checked that already while i was searching both here and on dlink forums for some solution. It's a disk that i bought around january 2009. It's not on the list provided by WD and doesn't support advanced formating. It's also on the list of supported drives by DNS323.

2. I'm preety sure it worked fine when i bought it. I was moving a lot of data from my Linux drive to NAS and still remember i got about 8MB/s speed (which was low for them then). I moved to Mac about a year ago and updated to 1.08 when it was released. I noticed the problem around that time but found it anoying last weekend when i had to move a lot of data compared to what i done previously. Performance drop could probably happend few months ago.

3. It's possible and i thought about it, but both e2fsck and smart doesn't report any error. I can also read the newly uploaded data with full speed what rather excludes bad blocks. The drive can be barely heard while uploading or downloading, there's just nothing beside that write speed that could suggest it's failing. Never heard also about write performance drop on failing drives as well.

I'll try with diffrent drive connected through USB (just out of curiousity) and also try to move that WDC disk to second bay to check if it changes something. Might also try connecting it to my Mac to check how it behaves, but it still does looks weird. Sadly, i don't have any other free disk to put into the NAS.

Last edited by Arcain (2011-02-22 16:22:15)

fordem · 2011-02-22 21:34:51

There's actually one more possible cause - fragmentation.

Arcain · 2011-02-23 01:03:10

Yes, i thought about fragmentation before but after checking few files with filefrag utility it seems to be fine. I've been using Linux and Linux filesystems for years and never experienced that much slowdown and only when writing on drive due to fs fragmentation. Even old FAT32 that should be defragmented at least once a month never was that anoying.

I did the other checks the USB drive i connected doesn't seem to be stable enough with NAS and hangs during the upload process. Swithing hdd in bays gives no effect as well. On the other hand, i also installed and mounted that drive on second PC running Slax for a moment. As expected, write speed is about 1MB/s while i can still copy any file from that drive to another with over 60MB/s (fuse-ntfs3g probably limits it). In fact, when writing to disk the transfer seems to jump for a while then stops and starts again. I'm currently in a progress of extended smart test but most likely the drive is really dying even tho i found the issue really weird. I'm gonna do the backup while i can still read data from it and reformat just to check if it might help for some reason but really doubt it.

Lucky, i got into solving the issue about time since the disk is in fact older that i though. WD drives gets 3 years warranty and even tho WD website says that one exipred on 10th feb this year i still have about 20 days to deliver it my local store for possible replacement.

Last edited by Arcain (2011-02-24 01:00:59)

Arcain · 2011-02-24 01:02:05

Just an update.

Managed to backup all the data and format it somehow to NTFS with quick format since which took like 10 minutes while regular kept going and going. Formating to ext3 simply stucked, reiser produced unreadable fs after formatting. Even those fresh NTFS formatted disk still get results with speed being close to 1MB/s if it comes to writing anything on the disk and locking it up almost completelly. Sometimes Windows report file copied while disk monitor still claims it's being written. Smart after all those checks report abnormal (above 180) disk spin up time as the only issue while both short and extended tests done yesterday went just fine.

What i'm curious about now is if any function, like a disk sleeping or standby mode for instance could lead to that kind of issue.

DSM-G600, DNS-3xx and NSA-220 Hack Forum

Announcement

#1 2011-02-22 13:31:22

Weird disk issue, very slow when writing.

#2 2011-02-22 15:40:48

Re: Weird disk issue, very slow when writing.

#3 2011-02-22 16:16:50

Re: Weird disk issue, very slow when writing.

#4 2011-02-22 21:34:51

Re: Weird disk issue, very slow when writing.

#5 2011-02-23 01:03:10

Re: Weird disk issue, very slow when writing.

#6 2011-02-24 01:02:05

Re: Weird disk issue, very slow when writing.

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