1. Integrating Disk into Backup for Faster Restores
Presented by
W. Curtis Preston
President
The Storage Group, Inc.

2. Tape backups are taking too long
High speed tape drives in a library are the standard, but the cost of these units causes many people to cut corners elsewhere
The nature of tape drives also creates difficulty when creating off-site tapes
Many people aren’t utilizing the tape drives properly, and are not getting all their backups done
Also, many are not creating off-site copies
Stand-alone tape drives must be swapped

3. Tape drives – the advantages
High speed, low cost
Good archival solution. Allows multiple copies without significant cost.
Lots of new tape drives on the market
9940B (30/70 MB/s)
AIT-3 (15/30 MB/s)
LTO (15/30 MB/s)
Super DLT (11/22 MB/s)

4. Tape - the challenges Tapes are now too fast!
Must use multiplexing to stream them during network backups
Must use higher multiplexing values than ever before, hurting restore performance even more
Tape to tape copying takes time, and multiplexing increases that time – especially if you de-multiplex
Must perform regular full backups to reduce number of tapes required for restore
Incremental backups do not supply enough data to stream a tape drive.

5. Tape - the challenges (2)
Cannot write to single tape drive from two shared servers simultaneously
Single tape can cause large restore to fail
You never know if a tape is good until you really need it

6. Still not making off-site copies
Assuming copy is same speed as backup, must buy at least twice as many drives to perform copies in one day
If copy is not same speed, must accept longer copy window or buy more tape drives
Additional drives cost a lot of money
Result: Many people still not making off-site copies

7. Solution: New backup media
Really inexpensive disk arrays
IDE/ATA based
Addressable via Fibre Channel, SCSI, Firewire, NFS, or CIFS
JBOD and RAID configurations (Use their RAID controller or a software volume manager.)
As low as $5,000 per TB for off-shelf units, $2,000 for build-your-own units!

8. What to do with them?
Buy enough disk for two full backups and many, many incremental backups (Can roll full backups)
Connect array to clients or backup servers via Fibre Channel & SANs, or GbE & NFS/CIFS

9. What to do with them? (2)
Back up to disk first using your backup software of choice
Duplicate disk backups to tape, send off-site
Except in disaster, restores come from disk
Maybe place (another?) disk unit off-site and replicate to it

10. What to do with them (3)
Most backup products do things that are not necessary when backing up to disk
Occasional full backups
Backing up redundant files
Incremental backups of entire files
New products designed to backup to disk
Forever incremental w/o performance hit
Some even eliminate redundant blocks across hosts

11. What to do with them? (4)
Replicate many clients to a central array, back that array up using backup software, and duplicate to tape for off-site copies
Allows you to use replication without the cost of traditional RAID arrays

12. What to do with them (5)
Could also use software-based RAID to create additional mirror, and split mirror for backups
Gives you BCV functionality for a fraction of the price!
Backup large databases with no I/O overhead on server!

13. Why would you do that? Don’t require constant stream
No need to multiplex on most disk devices
Depending on implementation, multiplexed backups may still be faster on disk
If you did multiplex your disk backups, you could easily de-multiplex the tape copies with no performance penalty
NFS/CIFS devices can be used simultaneously by many clients, without needing to stream each device

14. Why would you do that? (2)
Incremental backups with little data will not hurt performance of other backups
Protected via monitored RAID -- the loss of a single disk would be monitored and repaired, while the RAID group continued to protect the data
Disk to tape copies are easier than tape to tape copies
Could perform infrequent full backups without increasing the chance of failure
Full backups can be performed less often, saving networks and CPU utilization

15. Why not do everything to disk?
Archiving purpose of backups requires older backups to be available
Tapes still much cheaper, allowing for multiple, stable copies to be put on “the shelf” on-site or off-site
Tapes not susceptible to filesystem corruption

16. Issues… Staging process needs automation Increase ease of recovery
Need to automatically move data from disk to tape without removing from disk
Should allow you to leave backups on disk ALAP, and automate moving data to tape when necessary (policy based, not just retention based.)
Increase ease of recovery
Need to be able to import disk images
More products should support the creation of a “Synthetic Full,” creating a full from many incrementals
Backup twinning should be able to go to disk and tape

17. In Short Doing backups to inexpensive disk first allows for
Faster, easier backups – especially incremental backups
Easier creation of offsite tapes
Easier restores both on- and off-site
Many other features
A directory of ATA Fibre & SCSI addressable arrays is available at:
Questions to

18. Thank you!
W. Curtis Preston
President
The Storage Group, Inc.