On 10/5/13 11:46 PM, Miroslav Lachman wrote:
Julian H. Stacey wrote:
Has anyone else noticed how hot USB sticks can get when used for backup ? & also that IO errors occur after a while, which go away after a cold reboot.


Not the whole stick, but the metal connector gets hot, so chip is
hotter still.  Obviously one won't notice this on large plastic
encassed sticks, but 2 main sicks I use are:
  sandisk 2Gig metal case "vendor" "0x0781"; "product" "0x5151";
  delock 8G miniature (~ 3mm of platic beyond plug)
     "vendor" "0x05e3" "product" "0x0727"

I usually notice this when I am updating (writing) a crypted (gbde)
UFS file systems using port/net/rdist6 (which only rewrites updated files).

Source data is 1,446,438 K bytes in 42,611 files so average
size of 34 K.  But a lot of the files are really small, (~/.* config
&  mail files etc, so as rdist will be updating each one sequentially,
&  each will take a read + write cycle on a stick block,&  as many
small files will probably map to the same stick block, thats
some concentrated cycles.

More stick detail at
http://www.berklix.com/~jhs/src/bsd/fixes/FreeBSD/src/jhs/etc/devd/jhs.conf

Quite often I have to reboot my target host that has a stick inserted,
I believe regardless of OS version on USB target host

Possibly there might be less heating when only reading (as read
cycles are also quicker), but mainly I'm backing up, writing.

I was thinking of making a heatsink to clamp to a USB socket on an
extension cable, but before that I'll try hanging a USB extension cable
adjacent to a case fan.

I have a few USB sticks, some of them are really old (and fast!), for example 512MB A-Data with 200x speed, or 8GB 133x. These fast sticks are almost cool. Some cheap modern sticks are hot even if used as read-only for booting ZFS backup server, where whole base system is on UFS USB stick monted read-only and all writes are on ZFS partitions of 4 HDDs. Even in this RO scenario, the hot stick died after about 2 years. Writes on it was made about 3 times a year because of system or ports updates.

So in my case: newer -> cheaper -> slower -> hotter = shorter life.

actually, hotter is not always worse in Flash.
Warner can say more in detail but hot is good in some case while cold is best when you put the device on the shelf.


Miroslav Lachman
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