# DVD-Ram: To use or not to use pktcdvd / DVD-Ram awfully slow

## henfri

Hello,

I'm trying to store data on a DVD-Ram. I simply mounted it and could write it. But sadly, the writing is awfully slow. For the first 5 seconds its around 9MB/s, but then it slows down to 500 kb/s. 

In a HowTo I read about pktcdvd. It is supposed to speed this up. In fact, I reach about 1 MB/s with it. Still too little in my opinion. On the other hand, other HowTos explicitly suggest not to use pktcdvd with DVD-Ram, as packet writing is supported in Hardware in Case of DVD-Ram.

My Fstab looks like this:

/dev/cdrom      /mnt/cdrom      auto    rw,noauto,user,noatime,exec,iocharset=UTF-8 0 0

What's correct now?

Greetings,

Hendrik

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## hfk

Hello,

yes DVD-RAM is slow   :Crying or Very sad:  .

It depends on the media you use. The standard speed is 2xDVD but it will be slower because the data will be reread for verification. I am using DVD-RAM for backup. There speed is not the problem but security. The slower media are more secure than the faster. The slower media can be more often rewritten. The fast media are very expensive.

I would not use pktcdvd because the standard UTF file system includes a block management to extend the life of the media.

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## henfri

Hi,

I don't know what 2xDVD is in MB/s, but I suppose, it's a lot more than 300 kb/s, that I'm currently at.

What speed do you reach?

Greetings,

Hendrik

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## henfri

By the way: Do you use the pktcdvd, or not?

Greetings,

Hendrik

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## salahx

pktcdvd isn't a filesystem. Rather, its closer to the device mapper. The problem is DVD writers read and write in 32kb blocks (16 2k sectors), but the drive's firmware give illusion of per-sector granularity, by reading a 32k block, making the changes, then writing them back. Problem is, most drives do a terrible job. Enter pktcdvd - it basically caches and schedules the writes more to the driver's liking, thus making it MUCH faster. (Note that you HAVE to use pktcdvd for CD-R(W) and DVD-R(W), but not DVD+R(W) or DVD-RAM). Once the drive is mapped via pktcdvd, filesystem (like UDF) cna be created the usual way, and read or written to like any other block device.

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## henfri

Hi,

thanks for the clarification.

But, as I said, using pktcdvd didn't speed up the writing. Over the whole day, I was able to record two DVD-RAM only.

Still: Many sources say, that using pktcdvd is not neccessary for current Kernels.

Greetings,

Hendrik

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## pappy_mcfae

I don't have pktcdvd installed on this machine or my Compaq laptop, and I can crank out DVD's in no time flat. True, I haven't tried DVD-RAM, but I can't see how a different medium can bring things to a crawl in the manner you describe. If you are burning in a GUI environment, and you are also running hal/dbus, you should eliminate the invocation for your optical drives in your /etc/fstab file. It is redundant, unnecessary, and might be the cause of your problem in the first place.

Good luck.

Blessed be!

Pappy

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## henfri

Hello,

you can find numerous posts in forums etc, concerning slow DVD-Ram wrinting under Linux. It might not be a DVD-Ram problem but a UDEV Problem, but still...

I'm not using a GUI for recording. I use the shell (cp) or the MC.

Greetings,

Hendrik

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## hfk

I got 0.85 MB/sec using a USB LG recorder.

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## pappy_mcfae

Well, I guess I'm not going to use that particular media any time in the near future.

Blessed be!

Pappy

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## hfk

Hi Pappy,

you are right. I use DVD-RAM only for Backup of data to be saved for a long time AND therefore I use the slow DVD-RAM because they are more secure and cheaper.

For backup a USB-HD is much faster. For music, video etc. DVD are much cheaper.

Greetings,

   Heiner

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## henfri

Hi,

0.85 MB/s would be great. Double of what I achieve at the maximum (in fact I usually reach 200 kb/s only).

Could you please post your /etc/fstab entry for that drive?

What drive is it?  Mine is a LH-20.

Regards,

Hendrik

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## henfri

Hello,

one more important fact:

The system reacts very "sluggish" when I copy files to the DVD-Ram. This make things even worse.

The CPU-Load is not limiting though.

How can I "debug" this?

Regards,

Hendrik

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