Intel AS/400 RISC Server, 170 Servers manual Save and Restore Scaling using a Virtual Tape Drive

15.15 Save and Restore Scaling using a Virtual Tape Drive.

A 570 8 way System i was used for the following tests. A user ASP was created using up to 3 571F IOAs with up to 36 U320 70 GB DASD on each IOA. The Chart shows the number of DASD in each test and the Virtual tape drive was created using that DASD.

The workload data was restored into the system ASP and was then saved to the Virtual tape drive in the user ASP. The system ASP consisted of 2 HSL loops, a mix of 571E and 571F IOAs and 312 - 70GB U320 DASD units. These charts are very specific to this DASD but the scaling flow would be similar with different IOAs the actual rates would vary. For more information on the IOAs and DASD see Chapter 14 of this guide. Restoring the workloads from the Virtual tape drives started at 900 GB/HR reading from 6 DASD and scaled up to 1.5 TB/HR on the 108 DASD. The bottle neck will be limited to where you are writing and how many DASD are available to the write operation.

Large File Virtual Tape Scaling (SAVE) Write to Virtual tape

RAID5 SAVE RAID6 SAVE MIRRORING SAVE

	800
	700
GB/HR	600
	500
	400
	300
	200
	100
	0

	D			D	D	D	DASDDA			D	D	D	D	D	D	D		D		D	D	D		D
	D	DA		DA	DA	DA				DA	DA	DA	DA	DA	DASD			D		DA	DA DA
	AS		S S S S						S S S S S S							AS AS S						S	S
6	12	18		24	30	36		2	8	4	60	66	72	78	4		0		6	02		8
								4	4	5					8	9		9			0
																				1	1

User Mix Virtual Tape Scaling (SAVE) Write to Virtual Tape

RAID5 SAVE RAID6 SAVE MIRRORING SAVE

	300
GB/HR	250
	200
	150
	100
	50
	0

	DA DASDDA DASDDA					DA	DASDDA		DASDDASDDA DASDDA DASDDASDDA DA DASD
	SD		S			D		SD			S		S						SD S
					S S
6	12	8	24	0	6	2	8	4	60	6	72	8	4	0	6			2		08
		1		3	3	4	4	5		6		7	8	9	9		0
																1			1

IBM i 6.1 Performance Capabilities Reference - January/April/October 2008
© Copyright IBM Corp. 2008	Chapter 15. Save/Restore Performance	259