Which BSD - Flash Drive

Chuck Swiger cswiger at mac.com
Fri Apr 7 17:29:10 UTC 2006


Gayn Winters wrote:
>> [mailto:owner-freebsd-questions at freebsd.org] On Behalf Of 
>> Malcolm Fitzgerald
[ ... ]
> http://www.crucial.com/kb/answer.asp?qid=4088
> 
> Where they rate their own flash at 1,000,000 read/write cycles.

The typical flash drive used to be rated for about 10,000 writes, but the 
better vendors do better.  :-)

They've also started doing things like "wear leveling" by rotating the 
sectors being written to, which help avoid hotspots forming which wear out 
earlier (ie, the directory entry for / or /tmp).  But you need to look for 
that feature in your flash drives as the low-cost ones typically won't have it!

You can help things out a lot by disabling file access time updating 
("noatime" flag to mount), and by using RAMdisks and a no-swap config, as 
someone else had mentioned.

But I'll repeat my caveat: if you want to run a general-purpose FreeBSD 
system, you're better off using a hard drive than flash.  Save using flash 
for dedicated appliances where you've taken steps to control writes.

-- 
-Chuck

PS: I'm seeing a relatively significant number of 5-8 year old Cisco boxes 
starting to wear out their flash chips and fail (ie, 3 out of about a dozen 
or so I've had contact with over the years).


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