Peter Salisbury wrote:
> Hi,
>
> I've just bought an internal IDE DVD writer for burning off-computer
> copies of backups. I got a couple of DVD-RAM disks because they are
> more stable through time and allow far more RW cycles than DVD-RW.
> But unless I'm missing something DVD-RAM really isn't much good for
> what I want it for.
>
> When transferring large files (for example one of my backup archives
> is 1.1GB) I get an average transfer speed around 1MB/s which is
> painfully slow.
>
> The drive says it supports up to 12x (~16MB/s) and the media are rated
> at 3x (~4MB/s). I have no trouble writing CD's at around 8MB/s so
> it's not a limitation of the overall system.
>
> On top of this, I only get 1MB/s with a udf file system on the DVD-RAM
> and the Linux udf system won't handle a file over 1GB. When I put an
> ext2 file system on the DVD-RAM the average transfer speed falls to
> 0.7MB/s.
>
> Is it really this bad? Has anyone had a better experience of DVD-RAM?
>
> TIA, Peter
>
Hello Peter
I use DVD-RAMs for backups via Amanda, which reports a write speed of
about 1100KBps on Panasonic '2-3x speed' discs.
A quick test:
$ time (dd if=/dev/zero of=/media/dvdram/2G bs=4096 count=524288; umount
/media/dvdram)
524288+0 records in
524288+0 records out
2147483648 bytes (2.1 GB) copied, 958.001 seconds, 2.2 MB/s
real 22m49.100s
user 0m0.108s
sys 0m3.132s
shows a throughput of 1.5MBps including the time to unmount the disk.
gkrellm was showing a transfer rate of about 1.5MBps while that was running.
I don't know if DVD-RAMs are supposed to run faster than that or not.
cheers
Chris
--
Chris Dennis cgdennis@???
Fordingbridge, Hampshire, UK
