independent test IBM FlashSystem 840

1. Performance test IBM FlashSystem 840
1
Performance Test IBM FlashSystem 840
Configuration available IBM FlashSystem 840:
- Available 8х Flash Module eMLC (max up to 12хFlash Module) 2TB (real 1,87TB), 1 - hotspare, 7 – in RAID 5
- Available 8x8Gb FC host interfaces (max up to 16x8Gb FC)
Declared vendor performance for IBM FlashSystem 840 up to 775K iops, block size 4KB 100%Random, 70%/30% Read/Write.
We perform tests for determination of achievable performance indicators IBM FlashSystem 840 in the existing configuration (only 8хFlash Module).
In the test landscape 32хLU IBM FlashSystem 840 were presented (over FC-SAN) two servers IBM POWER System S822 (4х8Gb FC - each server, total - 8x8Gb FC, It means that as much as in IBM FlashSystem 840) 16хLU on single server. Servers IBM POWER System S822 used with Dual VIOS and FC NPIV.
On each test server/LPAR, LU was aggregated using AIX LVM (stripe). Test data were placed on JFS2 file system with inline log and options - noatime, cio. File System (4TB size) was filled data> 80%, the amount of data used by all.
The first test showed a linear READ speed performance - more 5GBps (Diagram 1).
Diagram 1

2. Performance test IBM FlashSystem 840
2
The next test WRITE speed performance showed almost 2GBps (Diagram 2).
Diagram 2
The multi-thread test - 100% Random, Read/Write=80/20, block size 4KB – performance over 500K iops (Diagram 3).
Diagram 3

3. Performance test IBM FlashSystem 840
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Repeat test with multi-thread workload - 100% Random, Read/Write=80/20, changing the size of the data block (Diagram 4 – performance in iops, Diagram 5 – the response time of the disk subsystem in ms).
4KB
8KB
16KB
32KB
64KB
128KB
IBM FlashSystem 840
507724
325057
174311
90340
45839
23059
0
100000
200000
300000
400000
500000
600000
IOPS
Diagram 4 - IBM FlashSystem 840
100% Random, Read/Write= 80/20
0
5
10
15
20
25
4KB
8KB
16KB
32KB
64KB
128KB
ms
4KB
8KB
16KB
32KB
64KB
128KB
IBM FlashSystem 840, write ms
0.6
1.1
2.9
7.6
16.2
31
IBM FlashSystem 840, read ms
1.2
2.4
4.8
9.6
18.8
34.5
Diagram 5 - IBM FlashSystem 840
average latency

4. Performance test IBM FlashSystem 840
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And for the next test will leave the fixed data block size - 8KB, and will change the ratio Read/Write. As shown in Diagram 6 - maximum performance was achieved at a ratio other than 100% Read.
100%
Write
10%
Read
90%
Write
20%
Read
80%
Write
30%
Read
70%
Write
40%
Read
60%
Write
50%
Read
50%
Write
60%
Read
40%
Write
70%
Read
30%
Write
80%
Read
20%
Write
90%
Read
10%
Write
100%
Read
IBM FlashSystem 840
187480
199834
213311
226443
241190
257174
274482
296792
325265
385369
378269
0
50000
100000
150000
200000
250000
300000
350000
400000
450000
IOPS
Diagram 6 - IBM FlashSystem 840
100% Random, Read/Write= 0/100-100/0

5. Performance test IBM FlashSystem 840
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Next, consider some aspect - how to change the performance of IBM FlashSystem 840 when updating firmware? Vendors always recommend updating firmware in the minimal load window, but never specify that under this understanding ... 1K iops, 10K iops, 100K iops?
Generate a load of about ~ 100K iops - 100% Random, Read/Write = 80/20, the block size 8KB, and simultaneously start firmware update for IBM FlashSystem 840. As shown in Diagram 7 and 8, slow performance very short (directly while upgrading controllers - more detailed this situation is shown in Diagram 9) and a slight increase in response time is during the verification RAID stripes.
Diagram 7
Diagram 8
0
20000
40000
60000
80000
100000
120000
140000
16:10
16:16
16:21
16:27
16:32
16:38
16:43
16:49
16:54
17:00
17:05
17:11
17:16
17:22
17:27
17:33
17:38
17:44
17:49
17:55
18:00
18:06
18:11
18:17
18:22
18:28
18:33
18:39
18:44
18:50
18:55
19:01
19:06
Disk xfers
IO/sec
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
16:10
16:16
16:21
16:27
16:32
16:38
16:43
16:49
16:54
17:00
17:05
17:11
17:16
17:22
17:27
17:33
17:38
17:44
17:49
17:55
18:00
18:06
18:11
18:17
18:22
18:28
18:33
18:39
18:44
18:50
18:55
19:01
19:06
Disk Service Time msec/xfer

6. Performance test IBM FlashSystem 840
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Diagram 9

7. Performance test IBM FlashSystem 840
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Thank you for your attention!
Oleg Korol
November 2014
http://ua.linkedin.com/pub/oleg-korol/26/920/716/