Re: USB-Storage, slow speed with sync option

[Erik Slagter <erik@slagter.name>]

[-- Attachment #1: Type: text/plain, Size: 984 bytes --]

On Wed, 2005-09-14 at 12:27 +0200, Stefan wrote:
> >>When I copy files to my USB 2.0 Stick , my transferspeed are horrible in
> >>case I mount the device with sync option, the rates are around 50KB/s,
> >>doesn't really matter how big the files are.
> >>If I don't mount with option sync, then the speeds are as expected a
> >>couple of MB/s
> >Now do a complete benchmark and type "sync" after the cp command.

> I already did that:-)
> 
> With sync option, a test directory takes about 15min to copy.
> Without sync option about 20s and running command sync afterwards takes
> about 5-10s.
> 
> So roughly 15min compared to 30s

The problem is that with the "sync" option the metadata on the stick has
be written on every block write. That is not only terribly slow
(especially on a flash device), it also wears out certain sectors.
Compare it to using floppy's on a MS/DOS computer.

Why would you _ever_ want to use the sync mount option on a flash
device?

[-- Attachment #2: smime.p7s --]
[-- Type: application/x-pkcs7-signature, Size: 2115 bytes --]