USB drive on server?

[Ted Marshall]

From: "John Austin" <ja at jaa.org.uk>
Newsgroups: gmane.linux.redhat.fedora.general
To: <tim at birdsnest.maths.tcd.ie>; "For users of Fedora" 
<fedora-list at redhat.com>
Sent: Tuesday, October 23, 2007 9:40 AM
Subject: Re: USB drive on server?


> Dup from other thread
>
>> Over 10 year life time
>
> http://www.corsairmemory.com/_faq/FAQ_flash_drive_wear_leveling.pdf

The problem with the statistics given for Dynamic Wear Leveling is that the 
flash controller must be able to know which blocks are not in use by the 
filesystem.  AFAIK (and this is very difficult to verify one way or the 
other), consumer grade devices (at least) are only aware of FAT filesystems 
and only if there is only one partition on the device.  If you use ext2/3 or 
have multiple partitions (both typical for Linux) the controller cannot 
track blocks being freed by the filesystem and so any block ever written by 
the host will looks busy to the flash controller.  Therefore, writes will 
only rotate through the (small) pool of extra blocks maintained by the flash 
controller.

Also, AFAIK, few if any consumer-grade and, I suspect, few 
professional-grade flash devices do Static Wear Leveling.

The result is that the flash drive will burn out much faster than the 
statistics quoted.  How much faster, I am unable to compute.  It may still 
be adequate for your needs.  I don't know.