Bad Sectors?

[poland]

Device: Pogoplug V2
Drive: 32GB flash drive(Archlinuxx+Download area)

I have a Pogoplug V2 with archlinux installed which I use as a download rig. The thing is that recently I noticed that when I transfer the downloaded video over to my PC over wifi, the transfer speeds reduce all of a sudden. From 1.8 - 2.3Mbps it goes down to 13kbps for sometime, intermittently.

Teracopy registers an error which goes something like "Cannot read from source" which leads me to believe that the flash drive has developed bad sectors. But I have no clue.

Also, such videos that encounter transfer problems then do not play properly on my PC!!!
(mind you the download is flawless and so is the video)(If I start to play such videos directly from the flash drive rather than transfer first, it play flawlessly)

Please guide me what to do next as i am a novice in Linux. Thank you.

[sambul13]

Don't continuously save video downloads on a flash drive, use HD or SSD instead. Though your issue may be related to Wi-Fi local interference or hardware problems affecting transfer speeds and packets loss.

[poland]

I do plan to use a HDD but I am trying to ride out the artificially induced high prices. So, I will have to stick with the flash drive for sometime.

I am positive that my issue has nothing to do with any wifi interference. I had a similar suspicion at first so I maintained a clear LoS between the pogo and my PC and the error still occurred at the exact same moment on various files.

My PC and the pogo are perfectly fine so the culprit seems to be the flash drive. Besides, the error thrown by teracopy confirms that the error has something to do with the the flash drive.

PS.:
1) Please note that in some videos I have no errors at all (could point to particular sectors being bad).

2) Also, I remember in a instance I had to rehash and re-download a few winrar files because they reported CRC errors after transfer.

[sambul13]

$this->bbcode_second_pass_quote('poland', 'I')f I start to play such videos directly from the flash drive rather than transfer first, it play flawlessly.

[moonman]

Flash drives have wear leveling controller on it so whenever a block goes bad it will be mapped as such and will never be used again. There's a limit of how many blocks can go bad but I don't think this is your issue. You might have hit a memory wall and just don't have enough free ram. If you are brave enough you may want to try to use a BFQ I/O scheduler which may or may not even out the load on your flash drive. If that doesn't work, you can try noop scheduler. For BFQ you need to have the latest kernel 3.6.4 and the latest u-boot. Then you can try different mount options that should reduce the amount of writes on your flash drive: noatime,data=writethrough,barrier=0,nobh. The most important ones are noatime and data=writethrough.