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 drxsim tool to perform these checks.
In general, the network bandwidth can be checked with tools such as iperf, and iperf calculates the maximum bandwidth the network can make. drxsim injects I/O load into DRX from local drxsim and receives remote relayed data from remote drxsim to calculate the throughput that DRX can process on the network. Therefore, DRX will perform best when iperf's result is equal to drxsim's or when drxsim's is greater than it by compression. Please refer to drxsim usage guide for more information on how to use it.
Based on the above, the factors of optimization are summarized as follows:
Latency and throughput optimization on the local I/O side should be handled with optimization on the replication side. For this, please refer to the following. |
Performance for the DRX can be viewed through the CLI commands provided by the DRX.
This command checks the usage rate and latency of the BAB.
You can check the usage rate of the BAB set by calculation of "2.4. Physical Memory Specifications".
Output Sample
< general output > [root@c73-p1 dgkim]# drx-ctl mem all -------------------------------------------------------------------------------------- Name Capacity Use (Size) Full Counts -------------------------------------------------------------------------------------- DR-1-3-c73-p2-c73-p1 716800 [>>>>>>>.....................] 23% (163277) 0 10240 [............................] 0% (0) - -------------------------------------------------------------------------------------- DR-2-3-c73-p2-c73-p1 512000 [............................] 0% (0) 0 10240 [............................] 0% (0) - -------------------------------------------------------------------------------------- Active bab counts : 2 < verbose output > [root@c73-p1 dgkim]# drx-ctl mem all -v ---------------------------------------------------------------------------------------------------------- Name Capacity Begin End Use (Size) Full Counts ---------------------------------------------------------------------------------------------------------- DR-1-3-c73-p2-c73-p1 716800 340236152 504137496 [>>>>>>>.....................] 22% (160060) 0 10240 0 0 [............................] 0% (0) - ---------------------------------------------------------------------------------------------------------- DR-2-3-c73-p2-c73-p1 512000 64273922 64273922 [............................] 0% (0) 0 10240 0 0 [............................] 0% (0) - ---------------------------------------------------------------------------------------------------------- Active bab counts : 2 ---------------------------------------------------------------------------------------------------------- name Latency cur avg max min ---------------------------------------------------------------------------------------------------------- DR-1-3-c73-p2-c73-p1 TX BAB 00:00:00.000000 00:00:00.443516 00:00:06.765142 00:00:00.000101 RX BAB 00:00:00.000000 00:00:00.000000 00:00:00.000000 00:00:00.000000 Compress 00:00:00.000088 00:00:00.000087 00:00:00.001439 00:00:00.000001 Decompress 00:00:00.000000 00:00:00.000000 00:00:00.000000 00:00:00.000000 ---------------------------------------------------------------------------------------------------------- DR-2-3-c73-p2-c73-p1 TX BAB 00:00:00.000000 00:00:00.001627 00:00:00.004173 00:00:00.000261 RX BAB 00:00:00.000000 00:00:00.000000 00:00:00.000000 00:00:00.000000 Compress 00:00:00.000000 00:00:00.000113 00:00:00.001440 00:00:00.000001 Decompress 00:00:00.000000 00:00:00.000000 00:00:00.000000 00:00:00.000000 ---------------------------------------------------------------------------------------------------------- Active bab counts : 2 [root@c73-p1 dgkim]# |
This command checks the DRX statistics information.
Sample command.
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 |
The compression ratio is calculated as (original size / compressed size), so it is round down to 2 decimal places for readability.
< verbose output > [root@c69-1 bsr.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 bsr.d]# < use the filter option output> [root@c69-1 bsr.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 bsr.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 |
DRX can optimize by adjusting the buffer size and compression options.
Size of the buffer is set via "memlimit" value in "proxy" section of the bsr configuration file.
proxy { memlimit 1G; } |
DRX provides the following compression plug-ins.
Type | System | Level range | Remarks |
---|---|---|---|
ZLIB | SW | 1~9 | - |
LZ4 | SW | 1~9 | - |
NONE | - | - | OFF |
The command to set the compression plug-in is as follows.
Type | Commands | Example output | |
---|---|---|---|
ZLIB | drx-ctl set compress zlib [level] [connect name] |
| |
LZ4 | drx-ctl set compress lz4 [level] [connect name] |
| |
NONE | drx-ctl set compress none 0 [connect name] |
|
It is possible to change the number of threads processing packets.
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.
< Configuration > [root@c73-1 bsr.d]# drx-ctl set process-thread-count 10 Result: done. [root@c73-1 bsr.d]# < Check > [root@c73-1 bsr.d]# drx-ctl show all ... ip-verification=on process-thread-count=10 [root@c73-1 bsr.d]# |
For DRX Appliance, you can perform optimizations on the local replication I/O reception intervals that work with bsr. DRX is primarily designed to perform buffering in the application address space, so performance may vary depending on the receiving performance of the OS kernel of the appliance, which is directly linked to bsr. Therefore, you can tune the receive buffer of this OS kernel socket to further enhance RX receive performance. To ensure that the OS kernel has enough receive buffers, it is necessary to apply the following to the OS kernel.
Changing the value using sysctl should be aware that there is a risk that the system will crash. If you set an unreasonable value to the system, it may stop immediately, so it should be done after enough testing. |
[root@c73-1 bsr.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@c73-1 bsr.d]# |
sysctl -w net.core.rmem_max="2097152" sysctl -w net.core.wmem_max="2097152" |
The set value is not an absolute value and the performance result may be different depending on server and network environment. |