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Back ups with Tapes or CDRW

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by docrod

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I convinced a client to go with my recommendation and use a back up tape system 4/8 gig as way to back up her server. The hardware vendor down the street went behind my back and convinced her that CDRWs were cheaper and better to use as back ups. How do I explain to the client that CDRW's are not the way to go with this?

8 replies

by timwalsh

A lot depends on the amount of data she needs to backup on a regular basis.

Capacity: a single 4/8GB DDS tape will hold 4GB of uncompressed or 8GB of compressed date. A single CD (depending on type) will hold 650 or 700 MB of uncompressed data. I'm not aware of any CD burners that support data compression. Therefore, each tape could ostensibly hold the content of 12 CDs.

Time: Granted that the same amount of data can probably be burned faster on a CD than to tape (typical DDS 2 tape drive has a data transfer rate of approximately 1.2MB/sec and a 24X CD-RW has a data transfer rate of approximately 3.6MB/sec), ease of use comes into play. She can stick a fresh tape in the drive before she goes home and the backup will be complete when she comes in in the morning. Backing up to a CD-RW, she (or someone) will have to stand there and feed it CDs. Further, the server should be doing ANYTHING else during the burning process to prevent the dreaded "buffer over-run". At BEST, this would mean about 4 minutes per CD.

Software: Depending on the operating sytem being used, it may include its own backup utility. However, none of these will recognize a CD-RW as a valid backup device. Most backup software packages that WILL backup to a CD-RW are not designed to be used on Server operating systems (you will need to do a little homework here to verify this - look specifically at the solution this vendor is offering). Of course, if she only has a minor amount of data, shecould just use normal CD-burning software.

Storage space: A single DDS-2 tape takes up a lot less room than 12 CDs.

Growth: How fast are her data storage requirements growing?

All of this may be moot if only she has a minor amount of data(less than a single CD's capacity) to backup on a regular basis.

by sangkoml

Same as the first opinion said, you have to consider a lot of factor like the capacity and the backup speed need.
In term of price, if you choose CD-RW, you have to include the special backup software too. Becuase the basic backup tool (NTBackup) of NT4 and W2K is not support the CD-RW. Other than that the software that alway provide with CD-RW are not able to run on the server version of NT4 and W2K.
I have found a lot of good looking software for backup to CD-RW but none of them are free nor cheap.

by thechas

In my experiance, CD-RW disks are not archival in nature.
I have had several loose their formatting on me.

So, if the data set is small enough that CDs are viable, they should use CD-R for the weekly full backups, and limit CD-RW for the daily incremental backups.

They should also follow the same topalogy as a good tape back-up, and have 8 sets of CD-RW disks, and run a 2 week rotation on them.

Chas

by andrew.jewell

CD's (R or RW) are just not as manageable as tapes for several reasons:
1) Physical size
2) Robustness, i.e. resistance to environment:
CD's are susceptible to the following,
wheras tapes are less so:
a) Heat
b) Ultra-violet light
c) Scratches
3) Security - you can't normally password or
encrypt data with cd-writing software
4) Software support - standard backup programs
simply don't support CD-R(w)
5) Convenience of use - a tape drivedoesn't
have to be spoon-fed media

If discs are to be the chosen option, then maybe a DVD should be considered. Capacity equivalent to a DDS2 tape, but other factors comparable to CD's.

The most important factor in maintaining a good backup system is convenience: if the system is inconvenient, it will not be adhered to, and backup integrity will suffer.

Secondly, the goal of the backup system has to be decided. Is it intended to:
1) Provide for recovery of individual files - or -
2) Provide for disaster recovery, i.e. system rebuild?

Have you ever tried to rebuild a system from CD backups? I wouldn't want to try.

by lordinfidel

Everyone has made some excellent remarks as to why not to go with cd-r as a backup medium.\

Although don't rule it out, afterall there is a time and a place for everything.

But the regular backup of business systems should be done to tape.

and here's why and how you should present it to them

The normal every day joe schmoe small office w/o a dedicated IT staff will 10 - 1 odds not think about the importance of backing up, and if they do many not backup what they need to.

Backing up to cd means several things.

1. It is a much more manual process.
2. You have to carefully select what you want to backup.

A good tape back up strategy will allow you just to just eject/insert and go.

A good tape back up strategy should be automated so that the end user never has to think about it.

And if they forget to eject the tape, tha b/u will still go on.

However, in cd's defense. I do *permantely* store old user's e-mail and files, web logs, server logs, archived e-mail, etc to cd.

I do this to reclaim space on my servers and with the assumption that it will be permamnet. I also burn 3 copies. I keep 2 on site in a big folder, and 1 off-site in a cd-folder.

Speed and reliabilty and ease is all up for debate.

What you have to plan for is idiot proofing the system, and getting to the point where they do not have to think about.

Ejcet/Insert and go.

What is their data worth to them if it is lost?

by tbragsda

I know everyone wants somthing better than tape, but tape has worked for a LONG time. It is the proven method. The biggest point I think could be made is capacity. Im sure that even in a small shop, the data will over run a couple CDs capacity, and the user will start getting lazy about their backups.

Just a note, I realy like the HP SureStore DDS 6X24. Put a mag at the start of the week, replace the next (for most small shops).

What backup software are they using with the CDR?

by docrod

To answer the last question, they are using Nero burner program. At the present time a proposal was sent to the client and what caught her eye on the pros of tape back up was the "Load and Go" method from one of the repondents earlier. I appreciate all the feed back and everyone has helped tremendously on my proposal amunition. The hardware vendor down the street I will deal with at a later time.

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