Analyzing Data Using the VRAdv Command
Command
vradv -a
Syntax
vradv –a -n network_bandwidth –o network_outage_duration[h/d]
–d secondary_downtime [h/d] –b secondary_backup_interval
-f filename -v vol1 vol2…voln [-h]
Description
The vradv -a command enables you to analyze the data write statistics information that you have collected for a specific time duration. You can specify the various options available with the command to analyze the data according to the specific requirements.
Command Options
To analyze the collected data using the command line, run the vradv command with the required options from the command prompt. The following table lists the command options and their descriptions.
| Option
|
Description
|
|---|
-a
|
Specifies the analysis mode.
|
-n network_bandwidth
|
Specifies the network bandwidth available for replication. You can specify the unit after the network bandwidth using the following symbols:
k - to represent kilobits per second (Kbps).
m - to represent megabits per second (Mbps).
g - to represent gigabits per second (Gbps). For example, –n 1g
The default unit is Mbps (m).
|
-o network_outage_duration
|
Specifies the network outage duration. You can specify the unit following the duration using the following symbols:
h – represents hours
d – represents days
For example, -o 1d indicates network outage duration of 1 day.
The default unit is days (d).
|
-d Secondary_downtime
|
Specifies the Secondary downtime duration. You can specify the unit following the duration using the following symbols:
h - represents hours
d - represents days
For example, -d 2d indicates Secondary downtime duration of 2 days.
The default unit is days (d).
|
-b Secondary_backup_interval
|
Specifies the Secondary backup interval in number of days and is an optional value.
For example, -b 5 indicates that the Secondary will be backed up after every 5 days.
|
-f filename
|
Specifies the name of the file that contains the data write statistics. This can be in different formats such as csv, vxstat, or iostat.
|
-v volumes or disks
|
Specifies the list of volumes or disks for which the data needs to be analyzed. In case –v option is not specified then all the volumes or disks for which data write statistics is collected will be analyzed.
|
-h
|
Displays the help
|
If you run the command without specifying any options or with the -h option only, the help is displayed. If you specify the command with the -a option only, the command prompts you for the remaining inputs.
After specifying the command options, VRAdvisor prompts you to specify the file format. Depending on the file format, you are required to provide additional inputs. The following table lists the additional inputs that are required for each file format.
| File format
|
Additional input
|
|---|
cvs
|
None
|
vxstat
|
Block Size
|
iostat
|
Percentage of writes
(will need to specify either or both depending on the platform)
|
Example 1
The following example uses the collected data from the file .datafile.txt (vxstat format with block size 512KB) for the specified volumes vol1 and vol2, and displays the calculated SRL size for synchronous override mode, asynchronous replication mode, and for the specified Secondary backup window. It also calculates the network bandwidth required for synchronous mode. These results are calculated based on the input of network bandwidth of one Gbps, network outage of one day, Secondary downtime of two days, and Secondary backup window of seven days.
-
To analyze the collected data, use the following command:
# vradv -a -n 1g -o 1d -d 2d -b 7 -v vol1, vol2 -f datafile.txt
where the data analysis parameters have the following values:
| Parameter
| Actual Values
|
|---|
-a mode
|
analysis
|
-n network bandwidth
|
1 Gbps
|
-o network outage
|
1 day
|
-d duration
|
2 days
|
-b secondary backup interval
|
7 days
|
-v volume or disks
|
vol1, vol 2
|
-f filename
|
datafile.txt
|
-
At the prompt, select the file format. For this example, the format is vxstat.
-
VRAdvisor prompts you for the following values:
Block size (512 KB) : 512
The data analysis starts. The output is displayed as follows :
SRL size for synchronous override mode: 500 MB
SRL size for asynchronous mode: 2 GB
Network bandwidth required for synchronous replication: 2mbps
SRL Size for 7 -day secondary backup interval: 16 GB
Example 2
This example shows the use of the vradv -a command when no parameters are specified. VRAdvisor prompts you for the required information.
-
Enter the following commands at the command prompt:
# cd /opt/VRTSvradv/bin
# ./vradv -a
-
Specify the required information at the prompts and press Return to continue.
Enter information for Data Analysis:
Network Bandwidth [(k/m/g) default unit Mbps]: 2M
Network Outage Duration [(h/d) default unit days]: 5h
Secondary Downtime Duration [(h/d) default unit days]: 2h
File Name: # /opt/VRTSvradv/samples/vxstat/vxstat1.txt
Volumes: test_vol
Do you want to calculate SRL Size for specified Secondary backup interval? [y/n]: n
File Format:
1. csv
2. vxstat
3. iostat (Solaris)
Select the file format: 2
Block Size [value in bytes] : 512
VRAdvisor begins the data analysis and displays the following message:
Data analysis is in progress...
- After the data analysis is complete the results are displayed in the following format:
SRL size required for replication in Synchronous override mode is : 62.71 MB
SRL size required for replication in Asynchronous mode is :
75.04 MB
Network Bandwidth required for replication in Synchronous mode : 240.4 KBPS
Since the specified Network Bandwidth is less than what is required for replication in Synchronous mode,there may be a degradation of application performance due to a delay in application writes.
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