Designing a
Backup Architecture
That Actually Works
W. Curtis Preston
President/CEO
The Storage Group
curtis@thestoragegroup.com
What will we cover?
What are the design options?
•LAN-based, LAN-free, Client-free, Server-free
•NDMP
•Using disk in your backup system
What should I do with them?
•Sizing your server
What are the design options?
SAN: _______, ________, and ___________________ backup
NAS: NDMP filer to self, filer to filer, filer to server, &
________________
SAN NAS SAN
Disk Array
FC Data General
FC
Backup
NAS Server Server FC
FC Virtual tape
FC Switch IBM
Ethernet
Library or Hub
FC Switch
FC or Hub
NAS Server
Backup Client FC FC Router
IBM
SCSI SCSI
SCSI
NAS Server
Library
Backup Client
Library
_______________________________________________________________________
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Backup
LAN-based backups
Server
Standard method
Central backup server with _________________ Data General
clients backing up across the LAN
Simplest, least expensive design Tape
Library
____________________________________________
____________________________________________
HEWLETT
PACKARD
____________________________________________ d i gi t a l
____________________________________________
Disk Disk Disk
LAN-free backups
IBM
Disk Tape
FC Library
How does this work?
•________Reserve/Release
SCSI
•Third-party queuing system
IBM
SCSI
Disk FC FC
Levels of drive sharing SCSI
Restores SCSI
FC
IBM
Disk
FC Switch SCSI/FC
Router
_______________________________________________________________________
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Client-free backups
Back LAN primary 3 backup Back
Tape Up Data disk set mirror Up Tape
Library Srvr 2b Srvr 1 Srvr Library
A Transaction Logs B
2c
2a
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________________________________________________________________________
Client-free restores
1a
Back LAN 1b
primary backup Back
Tape Up Data disk set Tape
mirror Up
Library Srvr Srvr Library
2b Srvr
A Transaction Logs
2c
2a
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________________________________________________________________________
Server-free backups
3
backup
LAN 2 mirror SAN
Back primary
or w/xcopy
Tape Up Data disk set Tape
snapshot support
Library Srvr Srvr Library
A Transaction Logs
1
Server directs client to take a copy-on-write ___________________
Client and server record block and file associations
Server sends FileA
FileB
XCOPY request
to SAN
Block A Block C Block D
Virtual Disk Block F
Block B Provided by Block E
Disk Array
_______________________________________________________________________
_______________________________________________________________________
Server-less Restores
Changing block Backup Restore
locations
Image level FileA FileB FileA FileB (deleted)
________________
File level Block A Block C Block D Block B Block E Block F
restores Virtual Disk Block F Block A Virtual Disk
Block B Block E Block C Provided by Block D
Provided by
Disk Array Disk Array
Block C Block D Block B Block D
Block A
Snapshot Block F Block A Snapshot Block F
Block B Block E Block C or Block E
or
Mirror Mirror
Tape Tape
________________________________________________________________________
________________________________________________________________________
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NDMP tape
library
Backing up a filer: NDMP Server to Filer Filer
Filer to self Filer to to Filer to Filer
Server LAN library
Filer to filer
Filer to server
Server to filer
Similar to _____________backups
Filer Filer Filer
Other Backup Filer
Server Server to
Self
Tape library Tape library Tape library
________________________________________________________________________
________________________________________________________________________
Using NDMP
Level of functionality depends on the _____________________ vendors
•Robotic Support
•Filer to Library Support
•Filer to Server Support
•Direct ____________ restore support
•Image level backup
________________________________________________________________________
________________________________________________________________________
Using disk
ATA-based _____________________________ as low as $5/GB
(disk only, needs filesystem)
Special function arrays
•Quantum DX-30 looks and behaves like a Quantum P1000. Can be used as target
for “________________________” backups
(3 usable TB, $55K list, or $18/GB)
•NetApp R100 looks like other NetApp filer. Target for SnapVault and disk-based
backups, source for SnapMirror
(9+ usable TB, $175K list, or $18/GB)
________________________________________________________________________
________________________________________________________________________
First Step: Backup to disk
Use as a target for all ___________________ backups. (Full, too, if you can afford it)
For off-site storage, duplicate all disk-based backups to tape
Leave disk-based backups on disk
________________________________________________________________________
________________________________________________________________________
Second Step: Mirror to disk
Use “dumb” arrays and smart volume managers and replication software
Use _______________________ with replication built into them.
Most valuable methods have built in ________________________ snapshots
Mirror to disk, then backup to tape, or mirror to another disk!
________________________________________________________________________
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Sizing the backup system
Give it enough power
Not enough tape drives
Tape drives that aren’t fast enough
Not enough __________ in the tape library
Not enough bandwidth to the __________________
________________________________________________________________________
________________________________________________________________________
Don’t give it too much power
Streaming tape drives must be ______________
__________________ aggregate
If you don’t, you will wear out your tape drives and
performance
Must match the speed of the _______________ to the speed of the tape
You can actually increase your throughput by using fewer tape drives
________________________________________________________________________
________________________________________________________________________
Server Size/Power
I/O performance more important than ____________ power
CPU, memory, I/O expandability paramount
Avoid _________________ by ___________________ prospective server under load
________________________________________________________________________
________________________________________________________________________
Catalog/database Size
Determine number of __________________ (n)
Determine number of ___________ in cycle (d)
(A cycle is a full backup and its associated incremental backups.)
Determine daily incremental size (i = n * .02)
Determine number of cycles on-line (c)
150-250 bytes per _____________, per backup
Use a 1.5 multiplier for growth and error
Index Size = (n + (i*d)) * c * 250 * 1.5
________________________________________________________________________
________________________________________________________________________
Number of Tape Drives – All Tape
LAN-based Backup
•Buy _______________ as many backup drives as your network will support
•Use only as many drives as the network will support (You will get more with less.)
•Use the other half of the drives for ______________________
________________________________________________________________________
________________________________________________________________________
Number of Drives – Disk/Tape Combo
LAN-based Backup
•Buy disk system large enough to satisfy entire _________________ retention
period without deletion
•Buy enough tape drives to _____________________ each night’s backups.
Duplicate each night’s backups to tape, then take them out and send them
offsite
•Library should be large enough to hold _______________ days of backups.
(Only needs to hold duplicated tapes until they’re sent off-site.)
________________________________________________________________________
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Number of Drives – LAN-Free backup
Most large servers have enough _____________________ to back themselves up
within a reasonable time
Usually a simple matter of mathematics:
•8 hr window, 8 TBs = 1 TB/hr = 277 MB/s
•30 10 Mb/s drives, 15 20 MB/s drives
Must have sufficient ______________________ to tape drives
Filesystem vs. raw recoveries
Allow drives and time for duplicating
________________________________________________________________________
________________________________________________________________________
Library Size - slots (all tape environment)
Should hold _________ onsite tapes
On-site tapes automatically expire and get reused
Only offsite tapes require _______________________.
Should monitor library via a script to ensure that each pool has enough free tapes
before you go home
Watch for those ____________________________ messages
________________________________________________________________________
________________________________________________________________________
Library Size - slots (disk/tape environment)
Do all backups to ________________ wherever possible
Library only needs to hold the latest set of copies (three or four days worth).
Disk-based backups automatically ___________________ and space gets reused
Only off-site tapes require phys. mgmt.
Should monitor library and disk via a script to ensure that each pool has enough free
space before you go home
Watch for those downed drive messages
________________________________________________________________________
________________________________________________________________________
Configuring your server
Backup all drives
Make sure you are ____________________ your drives
Create an automated monitoring system
Establish standards wherever possible, and use them!
Resources
Directories of products to help you build a better backup system
http://www.storagemountain.com