restore(8) to UFS on USB key: terrible slow

[Hans Petter Selasky]

On Thursday 08 December 2011 07:37:12 Matthias Apitz wrote:
> Hello,
> 
> I encounter the following problem with UFS file systems on USB keys,
> i.e. the problem is not only with one key, but with all I have; the key
> in question here is:
> 
> Dec  7 22:17:47 tinyCurrent kernel: umass0: <Generic Mass Storage, class
> 0/0, rev 2.00/1.02, addr 3> on usbus4 Dec  7 22:17:47 tinyCurrent kernel:
> umass0:  SCSI over Bulk-Only; quirks = 0x4101 Dec  7 22:17:47 tinyCurrent
> root: Unknown USB device: vendor 0x058f product 0x6387 bus uhub4 Dec  7
> 22:17:48 tinyCurrent kernel: umass0:0:0:-1: Attached to scbus0 Dec  7
> 22:17:48 tinyCurrent kernel: da0 at umass-sim0 bus 0 scbus0 target 0 lun 0
> Dec  7 22:17:48 tinyCurrent kernel: da0: <Generic Flash Disk 8.07>
> Removable Direct Access SCSI-2 device Dec  7 22:17:48 tinyCurrent kernel:
> da0: 40.000MB/s transfers
> Dec  7 22:17:48 tinyCurrent kernel: da0: 7650MB (15667200 512 byte sectors:
> 255H 63S/T 975C)
> 
> and the system is:
> 
> $ uname -a
> FreeBSD tinyCurrent 9.0-CURRENT FreeBSD 9.0-CURRENT #1 r214444: Thu Oct 28
> 10:56:32 CEST 2010
> 
> The key was formatted the usual way for receiving a complete FreeBSD
> system for installation purpose:
> 
> # fdisk -I da0
> # fdisk -B da0
> # bsdlabel -w da0s1 auto
> # bsdlabel -B da0s1
> # bsdlabel -e da0s1
> # newfs /dev/da0s1a
> # mount /dev/da0s1a /mnt
> 
> When I now bulk write a big file to the file system, the write
> performance is reasonable fast, even with blocks of 512 bytes,
> it gives 2 MByte / sec:
> 
> # dd if=usb.dmp of=/mnt/byte
> 10926520+0 records in
> 10926520+0 records out
> 5594378240 bytes transferred in 2538.942585 secs (2203428 bytes/sec)
> 

Hello!

The default block size of dd is 512 bytes. Try setting bs=65536 :-)

--HPS