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7.1. Optimization Factor

Optimization of DRX is accomplished by adjusting the DRX internal parameters or by changing the settings of the

7.1. Optimization Factor

Optimization of DRX is accomplished by adjusting the DRX internal parameters or by changing the settings of the system so that the buffering and compression functions provided by DRX can achieve optimal performance. The performance of DRX can be buffered up to 6 to 7 Gbps in a 10 Gbps network, and it can be said that the performance is adequate when the compression is 1.5 times more than that. However, these high-performance processing results ​​are based on the assumption that the DRX transmission network bandwidth of the TX side is sufficient, and usually can not show such throughput in the WAN interval. Therefore, in the case of such a high level I/O load state, It is difficult to optimize the performance of DRX in situations where random high level I/O load occurs in such a low transmission band, and it is necessary to check the bandwidth situation of WAN section in advance through proper level simulation for I/O load. DRX provides the drbdsim tool to perform these checks.

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• To view compression statistics, use the filter option in Output mode. 
  • The compression ratio represents the average value and the compression efficiency of the data to be transmitted can be checked.
  • Compression plug-in performance can be checked by the average compression time (cp-avg) and the decompression average time (dc-avg).

• Sample command.

  Code Block
  drx-ctl st all -v --filter=name,type,ratio,cur,best,worst,cp-avg,cp-cur,cp-min,cp-max,dc-avg,dc-cur,dc-min,dc-max

  
  

• Output Sample
  
  • The unit of size is Kilobytes.

  • The compression ratio is calculated as (original size / compressed size), so it is round down to 2 decimal places for readability.

  • The unit of compress(cp), decompress(de), encypto(ec), decrypto(dc) is microseconds.

    
    

    Code Block
    theme DJango title statistics collapse true
    < verbose output > [root@c69-1 drbd.d]# drx-ctl st all -v ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ name type tx rx t-raw t-net r-raw r-net ratio cur best worst cp-avg cp-cur cp-min cp-max ec-avg ec-cur ec-min ec-max dc-avg dc-cur dc-min dc-max de-avg de-cur de-min de-max ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ r0-c69-2-c69-1 data 184 0 13660 6821 0 1 1.93 0.00 18.07 1.00 0.000098 0 0.000001 0.013818 0 0 0 0 0 0 0 0 0.000189 0 0.000001 0.002338 r0-c69-2-c69-1 meta 0 0 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ All connections : 2, Established : 2 [root@c69-1 drbd.d]# < use the filter option output> [root@c69-1 drbd.d]# drx-ctl st all -v --filter=name,type,ratio,cur,best,worst,cp-avg,cp-cur,cp-min,cp-max,dc-avg,dc-cur,dc-min,dc-max ----------------------------------------------------------------------------------------------------------- name type ratio cur best worst cp-avg cp-cur cp-min cp-max dc-avg dc-cur dc-min dc-max ----------------------------------------------------------------------------------------------------------- r0-c69-2-c69-1 data 1.91 1.94 18.07 1.00 0.000088 0.000139 0.000001 0.013818 0 0 0 0 r0-c69-2-c69-1 meta ----------------------------------------------------------------------------------------------------------- All connections : 2, Established : 2 [root@c69-1 drbd.d]#

    Abbreviations

    AbbreviationDescriptionAbbreviationDescriptionAbbreviationDescriptiontxTX speedratiocompress average ratioecencryptorxRX speedcurcompress current ratio dcdecryptot-netTX network total relayed bytesworstcompress worst ratiot-rawTX network total transferred bytesbestcompress best ratior-netRX network total relayed bytescpcompressr-rawRX network total transferred bytesdedecompress

7.3. Optimization procedure

DRX can optimize by adjusting the buffer size and compression options.

7.3.1 Buffer size

Size of the buffer is set via "memlimit" value in "proxy" section of the DRBD configuration file.

proxy {
	memlimit 1G;
}

7.3.2 Compression type and level

DRX provides the following compression plug-ins.

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The command to set the compression plug-in is as follows.

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• • ----------------- All connections : 2, Established : 2 [root@c69-1 drbd.d]#

    
    

  • Abbreviations

    Abbreviation	Description	Abbreviation	Description	Abbreviation	Description
    tx	TX speed	ratio	compress average ratio	ec	encrypto
    rx	RX speed	cur	compress current ratio	dc	decrypto
    t-net	TX network total relayed bytes	worst	compress worst ratio
    t-raw	TX network total transferred bytes	best	compress best ratio
    r-net	RX network total relayed bytes	cp	compress
    r-raw	RX network total transferred bytes	de	decompress

    
    

7.3. Optimization procedure

DRX can optimize by adjusting the buffer size and compression options.

7.3.1 Buffer size

Size of the buffer is set via "memlimit" value in "proxy" section of the DRBD configuration file.

proxy {
	memlimit 1G;
}

7.3.2 Compression type and level

DRX provides the following compression plug-ins.

< Set compression plug-in to ZLIB >
[root@c73-qat-1 drbd.d]# drx-ctl set compress zlib 1 r0-c73-qat-2-c73-qat-1
r0-c73-qat-2-c73-qat-1: updated.
Result: 1 resource(s) updated.

[root@c73-qat-1 drbd.d]#

< Set compression plug-in to LZ4 >
[root@c73-qat-1 drbd.d]# drx-ctl set compress lz4 1 r0-c73-qat-2-c73-qat-1
r0-c73-qat-2-c73-qat-1: updated.
Result: 1 resource(s) updated.

[root@c73-qat-1 drbd.d]#

< Turn off compression plug-ins >
[root@c73-qat-1 drbd.d]# drx-ctl set compress none 0 r0-c73-qat-2-c73-qat-1
r0-c73-qat-2-c73-qat-1: updated.
Result: 1 resource(s) updated.

[root@c73-qat-1 drbd.d]#

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The number of threads is set to "process-thread-count" value in the configuration file. If you do not set it or input "-1", it will operate at half the number of CPU cores.

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/wiki/spaces/QA/pages/925794470

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• 8 Core / 1GBps 4H/W Zlib Level 116 Core / 2GBps8Commands

  
  

  Code Block
  theme DJango title process-thread-count collapse true
  < Configuration > [root@c73-qat-1 drbd.d]# drx-ctl set process-thread-count 10 Result: done. [root@c73-qat-1 drbd.d]# < Check > [root@c73-qat-1 drbd.d]# drx-ctl show all ... ip-verification=on process-thread-count=10 [root@c73-qat-1 drbd.d]#

  
  

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• Change TCP socket buffer size
  • Server used for testing : Server of Appendix D. Appliance Configuration Guide/wiki/spaces/PX/pages/901775481
  • References link : https://www.ibm.com/support/knowledgecenter/en/SSZTET_10.1/smpi01/smpi01_tysfbpjp.html
  • Default : 208KBytes

    
    

    Code Block
    theme DJango
    [root@c73-qat-1 drbd.d]# sysctl -a | grep net.core.[rw]mem net.core.rmem_default = 212992 net.core.rmem_max = 212992 net.core.wmem_default = 212992 net.core.wmem_max = 212992 [root@c73-qat-1 drbd.d]#

    
    

  • Modify command : Change the max entry to 2 MBytes.

    
    

    Code Block
    theme DJango
    sysctl -w net.core.rmem_max="2097152" sysctl -w net.core.wmem_max="2097152"

    
    

    Info
    The set value is not an absolute value and the performance result may be different depending on server and network environment.