Disadvantage and Advantage of Backup to Disk

[Optimus_Prime]

Hi,

What are the Disadvantage and Advantage of Backup to Disk?..We're planning to install Backup Exec 12.5 with 1TB Western Digital attached on it for our storage..Prior to implementation we want to know if this scenario is recommended.  Another question is that will it fall under a backup to disk or a removable backup to disk?

tnx

[CraigV]

Hi Optimus,

It's a built-in feature for a lot of backup software, not just for Backup Exec.
My pro's and cons would be as follows:

Pro's
1. Useful area for staging big backups to disk before duplicating to tape - this would cut down on a lot of time initially taken to back up to tape.
2. Additional storage for restores, or data that can be archived to a disk.
3. Fall-back device if your tape device fails - you'll be able to redirect to disk while it's being sorted out.

Cons
1. HDD failure - you will lose everything on the drive
2. USB time-outs - this would stop your backups (same with a SCSI time-out with a tape drive)

If you can leverage B2D and tape, I would recommend it. I am waiting for additional storage for our EVA 6100 to do the exact same thing.
To answer your last question, if it's an external disk (as in attached by a cable), it would be a removable B2D.

Laters!

[mdzale]

Hello Optimus,

if you don't have a tape device attached to your backup server (so you can setup some b2d to tape jobs) and tape library is too expensive for you to buy it, at least buy some kind net disk case which support mirroring... it is very small chance that both of disks in mirorring will die at the same time :)

But then again you shoud chekc your company data security polici to see recomendations for bacukup environment.

Regards,
Marinko

[PartTimeDAU]

Hello Optimus

Backup to Disk is a probably much slower backup than to a tape; in our environment (backing up to a separate raid with 8 disks) it is not half as fast as one tape drive. 

Also disk fragmentation needs to be cared for.

Regards,
Patrick

[Optimus_Prime]

Hi Craig,

Thanks for your reply. so your saying me that you recommend using the 1TB western digital? Is it best practice? Is it reliable? Well, my problem now is it seems like 1TB WD is not on the hardware compatibility list matrix of Symantec.  

[Optimus_Prime]

Hi Patrick,

Your right that backup to disk is much slower than to tape but in restoring a GRT staging to disk is faster right?

[CraigV]

Hey Optimus,

I don't think it really matters if it's on the HCL in this case. It would be attached via USB. TO my knowledge, there is no best practice around what specific hardware to use...this depends on your budget. I am lucky that I have an EVA 6100 at my disposal. Otherwise a normal USB-attached HDD would have been what I would have used.
Speaking from experience, duplicating to disk fpr GRT restores is quite quick, and I use this all the time. This includes to some of the site server local disks when need be.

[Optimus_Prime]

1TB Western Digital Caviar Green (SATA Hard Drive) is the exact type of storage that we're planning to use. It will act as a local disk. As per discussion with Support this morning he's not recommending me to use it since its not on the Compatibility List for it may or may not work. 

[teiva-boy]

 Personally, I use eSATA, NOT USB for better performance.

[Optimus_Prime · Accepted solution]

Below are the additional advantage and disadvantage of removable backup to disk I found out. Thanks for helping me out with this.

Advantage:

• Removable Backup to Disk is better than NAS device.
• GRT will work on B2D
• Support spanning of backup sets from one piece of media to another.

Disadvantage:

• Does not support concurrent operations.
• At this time Backup Exec does not support swapping out Hard disk drive.
• Removable hard disk drives can be removed and reattached at a later time but they cannot be swapped.
• Backup to disk is much slower than tape.

Reference:

http://seer.entsupport.symantec.com/docs/309594.htm
http://seer.entsupport.symantec.com/docs/275624.htm