Sony is finally delivering 50GB BluRay Discs!

[T2k]

Tape is a good backup medium. Where DVD does better is for archiving files for random access. If you back up a 4GB of data on tape and need a file from the last half of that tape, you have to scan through the tape until you get to the file. Off the DVD (HD DVD / BR), its accessible like a hard drive and quickly files the necessary files.
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Yep, random access and yes, it's a tradeout. However modern tapes are much-much faster.

I've used tapes for many many years. I've found that in the long term, tapes are not near as reliable as I've had with CD / DVD etc. Way too many times have I gone back to a backup two of three years and have not been able to read it anymore.

=I stronly disagree. Look, we use LTO tapes by the hundreds for years now and not one has failed yet. DLTs however were more sensitive to heat, I agree but heat kills DVDs even faster. Nevertheless we had dozens of CDs and DVDs dead, even brand name mediums, out of the same sized lot (ie hundreds).

You might want to check out Exabytes VXA: they claim they've boiled, frozen, dropped, even dropped into hot coffe and yet restored 100% data: http://exabyte.com/technology/tested/index.cfm

I would also point out that most tape drives I've seen always over state their read write rates.

I think you're confusing the compressed vs native speed issue here...

Even thought it say you can write at 20MB/sec, if the disk is limited to reading of only 10MB/sec, then you'll get 10MB or less on the writing to tape.

There's no disk like 10MB/s for long years now. Average IDE or SATA disks can read at least around 40-50MB/s anytime.

OTOH top tape systems like an LTO-3 can be faster than your average disk but those are designed for SCSI or more likely striped or other RAID volumes.

 

[berck]

Look, you love tape fine, but DVD and CD have their place and are much easier to use for random access. If I only want a system back up, tape is definitely the way to go. But if I'm just archiving personal stuff, the random access features of DVD and CD.

As far as read speeds, well, I've seen numbers like that but not consistantly. Small files are fine, but there is so much variation from system to system. I've had SCSI drive that would read and write at nearly 100MB/sec using Linux, but the same exact hardware under Windows was limited to 33MB/sec. But, if the file was larger than 100MB, forget it, speeds got slower.

I've done many speed test with disks and I seen much lower speeds than everyone claims. A lot of it has to do with the disk cache. I've written programs to figure out the limitations in both the drivers and the disk.

 

[T2k]

Look, you love tape fine, but DVD and CD have their place and are much easier to use for random access. If I only want a system back up, tape is definitely the way to go. But if I'm just archiving personal stuff, the random access features of DVD and CD.

But but but...



... it was my point as well. If you have to have random access then tape isn't the technology you want.

As far as read speeds, well, I've seen numbers like that but not consistantly.

Eh, 'seen numbers'? Run a test on your machine and you'll see.

Small files are fine, but there is so much variation from system to system.

Exactly smalls files are the ones you don't want to measure with, due its inconsistent and irrealistic results.

I've had SCSI drive that would read and write at nearly 100MB/sec using Linux, but the same exact hardware under Windows was limited to 33MB/sec. But, if the file was larger than 100MB, forget it, speeds got slower.

"Windows" is MS' OS brand name, it doesn't really tell me anything... it could be anything from v1.0 to XP SP2 or Server 2003 R2, FAT16, FAT32 or NTFS etc etc.
If it was an XP SP2 on NTFS then you had a fine linux but a sh!tty windows setup. By default Windows horribly fragments the filesystem, if you install/uninstall often then you want to defrag often as well. And there are other factors...
When Maxtor's Atlas 15K (formerly knows as Quantum) drives came out, I bought 3 of those 73 gig monsters (I/O was above 900 IIRC) and I mostly used under Windows and never had a problem for ~3 years straight.

I've done many speed test with disks and I seen much lower speeds than everyone claims.

I don't know what "everyone claims" means... how about throwing in some numbers? I did...

A lot of it has to do with the disk cache.

Right and with rotational speeds, writing technology, fragmentation etc etc.
Again: there's no modern disk that cannot sustain 20-30MB/s for a tape drive.

I've written programs to figure out the limitations in both the drivers and the disk.

Which one, may I ask? And what do you mean under limitations? It depends on the circumstances: random access, continuous acces etc...

 

[berck]

Ok, why should I provide you anything? when I give you numbers, you say they're wrong.

You provide things with nothing to back them up either. Just, oh a tape can write at 20MB / sec. Fine, I have my doubts about that. I've used many tape systems and NONE of them performed to what they were spec'd at.

Two of us here have stated issues about tape, but you have disagreed and said that we are wrong. They only time I've had problems with CD / DVD storage is when somebody doesn't store the content correctly (protective sleeve, case, etc). With tape, I have no idea why it will go bad. It just does. Not sure if its the tape head has warn out on the system or just moving from one tape drive to another. The tapes were stored properly in an vault that was temperature controled and it still went bad! That's is just a few of the many though.

Tape has its place and so does CD / DVD.

 

[T2k]

Ok, why should I provide you anything? when I give you numbers, you say they're wrong.

Did I? The only thing I said is wrong is your silly claim that hard drives can't sustain 10MB/s... and that's just downright funny to anybody who has at least a basic knowledge about today's hardware.

You provide things with nothing to back them up either. Just, oh a tape can write at 20MB / sec. Fine, I have my doubts about that. I've used many tape systems and NONE of them performed to what they were spec'd at.

Then you haven't used modern tapes for years. pal. It's nothing spectacular, it's normal.

Two of us here have stated issues about tape,

Not true. One of you said it's awkward and big which is RIDICULOUS compared to discs then you came with your old experience and there was a dead drive which - as we all know - could happen to anybody, let alone we did not hear anything concrete...

but you have disagreed and said that we are wrong.

Ummm care to show where did I say that without backing up my part with data/facts?I

They only time I've had problems with CD / DVD storage is when somebody doesn't store the content correctly (protective sleeve, case, etc).

Or heat, magnetic field etc. Keep on going...

With tape, I have no idea why it will go bad. It just does. Not sure if its the tape head has warn out on the system or just moving from one tape drive to another. The tapes were stored properly in an vault that was temperature controled and it still went bad! That's is just a few of the many though.

Tape has its place and so does CD / DVD.

Exactly my point...

 

[Foxbat]

I stumbled across this thread while killing some time babysitting my weekly backups.

Hmmm, lets see: backing up my live Exchange 2K3 server, I'm cranking out between 345 - 555MB/min across the LAN (gigabit on both servers, gb switches between the servers) going to a DLT IV tape library. That works out to 5.7 - 9.3 MB/sec real world.

Also, looking at an Oracle DB server backup session from earlier this weekend, it varied from 340 MB/sec to over 1.2 GB/sec. That's pretty much the max my DLT8000 drive can accept data due to the SCSI II bus. I've clocked the disk drives on that particular server at close to 40 MB/sec (Ultra320 SCSI RAID).

T2k, you said you used to use DLT and currently use LTO tapes. Did you look at SDLT? We are an old DEC shop, so we have a certain "fondness" for the DLT form-factor.

As far as the topic at hand, I don't know if a 50 GB optical disk at $1000/drive makes much of an impression. I can buy a 500 GB hard drive today for ~$700 (or less) and put a couple of those together and make a 2 TB archive with on-line access to my data for $3.5K. I'd need a jukebox mechanism, two $2K BluRay drives, and 40 BD-Rs @$50 each, and I'm over the cost of the faster HDD solution.

 

[berck]

Did I? The only thing I said is wrong is your silly claim that hard drives can't sustain 10MB/s... and that's just downright funny to anybody who has at least a basic knowledge about today's hardware.

I said
I would also point out that most tape drives I've seen always over state their read write rates. Even thought it say you can write at 20MB/sec, if the disk is limited to reading of only 10MB/sec, then you'll get 10MB or less on the writing to tape.

The statement is absolutely true. I never said that hard drives are limited. It was a point of reference. Besides, many USB and Firewire drives are limited to not much faster than those rates for continous reading and writing. FW is limited to 50MB/sec and USB to 60MB/sec, but they generally can't operate that fast and tend to be much slower than those numbers (10-20MB/sec range is typical).

Then you haven't used modern tapes for years. pal. It's nothing spectacular, it's normal.

I haven't been involved with them for a couple of years, I've used 1/4", 1/2", 8MM, DLT and tape farms. For my home I now use a backup system to an external firewire drive.

Not true. One of you said it's awkward and big which is RIDICULOUS compared to discs then you came with your old experience and there was a dead drive which - as we all know - could happen to anybody, let alone we did not hear anything concrete...

navychop said he had some issue on the tape storage. You told him to back up twice. Hence, you weren't disagreeing with him until he made the statement about disc eventually outpacing tape.

You disagreed with me about having reliabilty problems with tapes.

Ummm care to show where did I say that without backing up my part with data/facts?I

In response to navychop (about disc out pacing tape storage eventually), you said.

you couldn't be fruther from truth - similarly priced tape technologies are FAR FASTER than BR or HD-DVD.

Here are facts, atleast one part is based on what you said.

Tape writing is 20MB/sec.

Initial Blu Ray write speed is 4.5MB/sec
They are planning on 8x soon after release which will put it at 36MB/sec, and possibly 12x. So were exactly is navychop further from the truth?

Or heat, magnetic field etc. Keep on going...

Magnetic field on an optical storage device????? They use lasers now buddy. The magnetic fields can affect the drive, but not the media. I once used Magnetic-optical system they may have problems with magnetic fields, but not current CD/DVD systems. Besides, these same two things affect tapes.