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Re: USB drive on server?



From: "John Austin" <ja jaa org uk>
Newsgroups: gmane.linux.redhat.fedora.general
To: <tim birdsnest maths tcd ie>; "For users of Fedora" <fedora-list 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.


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