Intel AS/400 RISC Server Lower Performing Backup Devices, Medium & High Performing Backup Devices

15.5 Lower Performing Backup Devices

With the lower performing backup devices, the devices themselves become the gating factor so the save rates are approximately the same, regardless of system CPU size (DVD-RAM).

Table 15.5.1 Lower performing backup devices LossFromWorkLoadType Approximations (Save Operations)

Workload Type	Amount of Loss
Large Database File	95%
User Mix / Domino / Network Storage Space	55%
Source File / 1 Directory Many Objects / Many Directories Many Objects	25%

Example for a DVD-RAM:
DeviceSpeed *		LossFromWorkLoad * Compaction Factor
0.75	*	0.95 = (.71)	*	2.8 = (1.995) MB/S * 3600 = 7182 MB/HR = 7 GB/HR
0.75	*	0.95 = (.71)	*	No Compression * 3600 = 2556 MB/HR = 2.5 GB/HR

15.6 Medium & High Performing Backup Devices

Medium & high performing backup devices (SLR60, SLR100, VXA-2, VXA-320).

Table 15.6.1 Medium performing backup devices LossFromWorkLoadType Approximations (Save Operations)

Workload Type	Amount of Loss
Large Database File	95%
User Mix / Domino / Network Storage Space	65%
Source File / 1 Directory Many Objects / Many Directories Many Objects	25%

Example for SLR100:

DeviceSpeed * LossFromWorkLoad * Compaction Factor

5.0 * 0.95 = (4.75) * 2.0 = (9.5) MB/S * 3600 = 34200 MB/HR = 34 GB/HR

15.7 Ultra High Performing Backup Devices

High speed backup devices are designed to perform best on large files. The use of multiple high speed backup devices concurrently or in parallel can also help to minimize system save times. See section on Multiple backup devices for more information (3580 Ultrium-2, 3580 Ultrium-3 (2Gb & 4Gb Fiber Channel), 3592J, 3592E).

Table 15.7.1 Higher performing backup devices LossFromWorkLoadType Approximations (Save Operations)

Workload Type	Amount of Loss
Large Database File	95%
User Mix / Domino / Network Storage Space	50%
Source File / 1 Directory Many Objects / Many Directories Many Objects	5%

Example for 3580 ULTRIUM-2 Fiber:
DeviceSpeed		* LossFromWorkLoad * Compaction Factor
LG File	35.0 * 0.95 = (33.25)		* 2.8= (93.1) MB/S *3600	= 335160 MB/HR = 335 GB/HR
UserMix 35.0		* 0.50 = (17.5)	* 2.8= (49) MB/S *3600 =	176400 MB/HR = 176 GB/HR
Source	35.0	* 0.05 = (1.75)	* 2.8= (4.9) MB/S *3600 = 17640 MB/HR = 17.6 GB/HR

NOTE: Actual performance is data dependent, these formulas are for estimating purposes and may not match actual performance on customer systems.

IBM i 6.1 Performance Capabilities Reference - January/April/October 2008
© Copyright IBM Corp. 2008	Chapter 15. Save/Restore Performance	247