Date: Tue, 17 Jun 2008 11:36:18 +0200 From: "Julian Stacey" <jhs@berklix.org> To: usb@freebsd.org Subject: best block size for file systems on USB media ? Message-ID: <200806170936.m5H9aIJn085539@fire.js.berklix.net>
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Hi usb@freebsd.org Do USB flash memory sticks have cache ram ? What are best file system block sizes to write USB media (to maximise access speed) ? Any URLS to RTFM welcome ;-) I'm using mine to back up my personal tree of private data, (mail & tech notes & sources etc, lots of smallish files), I'm using /usr/ports/net/rdist6 to backup. My biggest stick, a 2G Sandisk Cruzer micro (vendor 0x0781 product 0x5151) is awfully slow (much slower per Meg than other manufacturers smaller sticks) (& other 2G Sandisk sticks bought in same purchase from same vendor are also awfully slow on Win-XP, so maybe these have less or no cache ram (if such things have cache at all ?) or maybe they were a fraudulent batch without cache when they should have had cache or ... ? ) Maybe some other sticks work on different block size ? Maybe for many of my small files, the stick needs to read a big block, before modifying a small chunk & writing back to block ? Block sizes was a question I'd meant to ask earlier, just for normal sticks with a normal FreeBSD FS on there, now it's become even more of an interest, using a BSD FS within an encrypted gbde partition ref. Read http://www.freebsd.org/doc/en/books/handbook/disks-encrypting.html which is slower still from encyption overhead (noticeable doing a reload into new empty FS). Some FS issues might be better discussed later on fs@freebsd.org, but first, what's known about USB hardware block sizes please ? Julian -- Julian Stacey: BSDUnixLinux C Prog Admin SysEng Consult Munich www.berklix.com Mail plain ASCII text. HTML & Base64 text are spam.
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