Posted on 2004-10-12
Last Modified: 2008-01-09
Hello all,

I was looking at getting a dell powerVault 112T.  When going through the purchasing options I noticed that the DLTVS80 drive for it was significantly more expensive than the DDS4 drive.  Would anyone happen to know what advantages DLT has over DDS?  

Thanks in advance.
Question by:joshuaemory
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
LVL 96

Expert Comment

by:Lee W, MVP
ID: 12288695

With my past job and a client they purchased SEVERAL dell tape drives and I think the failure rate was 75% - we replaced drives and whole units several times in the first few months of ownership.

I'll admit - this info is a year or so old, but we switched to Overland systems and they worked flawlessly (though I understand recently they've had problems with a couple units, but by this point the units are at least 2 years old.  
LVL 96

Accepted Solution

Lee W, MVP earned 250 total points
ID: 12288717
That said, DDS tapes hold 20 GB uncompressed, DLT tapes hold 40GB uncompressed.  SDLT does 160 or 300 GB, depending on the drive model.

DLT also has faster potential throughput.  SDLT faster still

DLT/SDLT is a larger tape, roughly 1x3x3 inches, where as a DDS is only a little larger than a microcassette tape.

If you're backing up large or relatively large drives, go with DLT or preferrably SDLT as I doubt your data stores are going to get SMALLER.
LVL 13

Assisted Solution

masterbaker earned 250 total points
ID: 12289071
Check out this link:

That has the specs on the three drive options (DDS4, DLTVS80, and DLTVS160).  

Basically you need to think about how much data you need to backup for your largest job (such as a nightly full backup of your data) and how quickly you need it done.

Do you need to only backup a few gigabytes over an entire evening?  Any drive will do for that.

Do you need to backup 80GB in a 4 hour window?  If so, the only option is the DLTVS160.

If you look at the 2nd page of that link, you'll see the drive speeds and storage.  DDS4 and DLTVS80 will backup around 11GB per hour.  DLTVS160 is about 33GB per hour.  

You just need to think about the size of your backup jobs, whether or not you want to swap tapes in the middle of a job, and the size of your backup time window.

By the way, I have had good experience with Dell tape drives.  I'm not sure if they are all re-branded ADIC drives, but I know at least a couple of models are.  ADIC makes great backup systems, so as long as Dell doesn't mess with them, they'll be good as well.  You'll always find people with good and bad experiences with every brand.  No one is perfect. :)

WordPress Tutorial 4: Recommended Plugins

Now that you have WordPress installed, understand the interface, and know how to install new parts, let’s take a look at our recommended plugins.

LVL 96

Expert Comment

by:Lee W, MVP
ID: 12289178

I agree with the no one is perfect.  My experience is with:
TWO PowerVault T130 (DLT)
ONE PowerVault T136 (SDLT)
TWO PowerVault T120 (DDS)
ONE PowerVault T120 (DLT1)

The only unit that never gave me problems was the T120 DLT1.  The two 130's were consecutive systems; one replaced the other after NUMEROUS drive failures.  Then the other had a few failures before it finally settled down.
The 136 worked great for 6 weeks, then we couldn't use it for a month
The 120 DDS worked for a while then got jamed and we had to send it back to Dell - they never returned the tapes - WITH backup data.

MAYBE they improved over the past year, but I've used ATL, HP, and OVERLAND systems, and never had such consistant problems.
LVL 56

Expert Comment

ID: 12289931
DDS sounds cheaper than DLT and the media is less but when you look at the cost over time you find that DDS heads wear out quicker than DLT and the media wears out much qicker, probably 4 times as fast.  With DDS there are guide pins and rollers that touch the recording surface wearing it out, the only thing that touches the recording surface of DLT is the head.

Author Comment

ID: 12290588
Thanks a lot for the advice everyone.  You've all been very helpful.  Against my nature I've decided to not be stingy and go for the DLT drive...
LVL 13

Expert Comment

ID: 12290983
Good choice!

If you do want to save a few bucks, you can often pick up new DLT tapes on eBay for a fraction of the cost!  I have purchased several lots of 5 tapes on there for less than 1/3 the new price.  

Just steer clear of used tapes.  You never know what you're going to get, and backups are important!


Featured Post

Ransomware-A Revenue Bonanza for Service Providers

Ransomware – malware that gets on your customers’ computers, encrypts their data, and extorts a hefty ransom for the decryption keys – is a surging new threat.  The purpose of this eBook is to educate the reader about ransomware attacks.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Create your own, high-performance VM backup appliance by installing NAKIVO Backup & Replication directly onto a Synology NAS!
This article aims to explain the working of CircularLogArchiver. This tool was designed to solve the buildup of log file in cases where systems do not support circular logging or where circular logging is not enabled
This video teaches viewers how to encrypt an external drive that requires a password to read and edit the drive. All tasks are done in Disk Utility. Plug in the external drive you wish to encrypt: Make sure all previous data on the drive has been …
This Micro Tutorial will teach you how to reformat your flash drive. Sometimes your flash drive may have issues carrying files so this will completely restore it to manufacturing settings. Make sure to backup all files before reformatting. This w…

624 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question