Parallel writes is a configurable feature that affects the number of Web service requests that will operate in parallel across an instance of DryvIQ on a given node. It is important to note that increasing the number of parallel writes does not always equal faster or better transfer performance. A long list of concepts must be taken into account.

Parallel Writes and Memory Usage

A migration job in DryvIQ does not use a fixed amount of memory. Memory usage for individual jobs varies based on several factors, the most significant being the number of files and how those files are distributed (all in one folder, throughout sub-folders, etc.). DryvIQ recommends preserving the system default for Directory Item Limits to avoid excessive memory usage related to content distribution. The main factors for memory usage for a DryvIQ node will be the number of concurrent jobs, the number of parallel writes for the jobs, and the memory impact of the specific jobs.

If memory issues occur due to increasing the Directory Item Limit or parallel writes, there is no mitigation other than reducing the number of current jobs or breaking up the source content into multiple jobs. DryvIQ does not self-limit; it will keep using memory until it runs out and eventually reaches the environment’s max. Reaching an environment max may result in a non-graceful termination of DryvIQ that could result in jobs re-transferring files, permissions, or metadata. In the case of larger jobs being stopped in this manner, they will enter recovery mode, continue to use all the memory, then get stopped again, in a loop, causing a loss of throughput.

Default Parallel Writes

The default parallel write value is 4, 8, or 12, depending on the number of CPU logical processors on the machine running the DryvIQ service.

• If the CPU Logical Processors is 2, the default parallel writes value is 4.
• If the CPU Logical Processors is 8, the default parallel writes value is 8.
• If the CPU Logical Processors is 32, the default parallel writes value is 12.

Changing the Global Parallel Writes

The global parallel writes setting changes the settings for all jobs. If you want to change the setting for a single job, you must use the REST API to update the configuration for the individual job. Refer to “Parallel Writes Per Job” for more information on updating the parallel writes setting for an individual job. All nodes will be updated with the new setting if you have multiple nodes.

1. Click Settings in the left menu.
2. Select Performance.
3. In the Requested field, type the number of parallel writes you want to set.
4. Select Save.

Bandwidth throttling allows you to limit the upload or download bandwidth DryvIQ's migration jobs use. You can set throttling to take effect on certain days and at certain times. This is a global setting that affects all migration jobs. Jobs running when you set this parameter will not pick up the setting until the next job run. Clusters will pick up the parameter changes, and all new jobs will use the new settings.

Defining Bandwidth Throttling

1. Click Settings in the left menu.
2. Click Performance.
3. Verify the Bandwidth Throttling toggle is turned on. (The toggle should be green.)
4. Click Create next to Upload Throttle or Download Throttle, based on which throttle configuration you want to add. The corresponding Bandwidth Throttle modal appears. (Note that both modals contain the same settings.)
   
   
    
5. In Maximum Bandwidth, enter the maximum number of bytes you want to set per second. This sets the maximum speed outside of the configured timeframes. This field is optional. If you leave it blank, DryvIQ will use an unlimited value, uploading or downloading whatever it can.
6. Click Add another timeframe. Additional fields display.
7. Use the Timeframe list to select the days of the week the schedule applies. This is a multi-select list, so you can select as many days as you like.
   
   
    
8. Use the Starting and Ending fields to specify the start time and end time for the bandwidth throttling you want to set. Click the clock icon and use the clock tool to select the time.
   
   
    
9. In Bandwidth, enter the bytes per second value you want to set.
10. Click Add another timeframe and repeat steps 7-9 to create another schedule for a different time of day or a different set of days if needed. Continue to add additional timeframes as needed.
11. If you want the upload and download throttling to be the same, select the Apply configuration to both throttles box. This will copy the configuration to both settings, so you don’t have to enter it again.
    
    
     
12. Click Done to save the settings and close the modal.
13. The configuration(s) will be displayed on the Performance tab.

Editing a Timeframe

You must edit the upload and download configurations separately, even if you used the Apply configurations to both throttles option when creating the configurations.

1. Click Settings in the left menu.
2. Click Performance.
3. Click Edit next to the throttle configuration you want to edit.
4. Edit the fields as needed.
5. To remove an individual configuration, click Remove next to it.
6. Click Done to save the settings and close the modal.
7. The adjusted configuration(s) will display on the Performance tab for your reference.

Deleting a Configuration

1. Click Settings in the left menu.
2. Click Performance.
3. Click Delete next to the throttle configuration you want to remove.
   
   
    
4. The configuration is removed.

Disabling Bandwidth Throttling

If you disable bandwidth throttling, DryvIQ will retain any configuration settings added, so they can be applied again by enabling bandwidth throttling.

1. Click Settings in the left menu.
2. Click Performance.
3. Turn off the Bandwidth Throttling toggle. It will turn gray and display an x to indicate it’s been disabled.

The logging level determines the amount of information captured and included in the application logs. You would change the logging level to capture specific information to troubleshoot issues. If you have multiple nodes, all nodes will be updated with the new setting.

Logging Levels

Changing the Logging Level

1. Click Settings in the left menu.
2. Click Performance.
3. Select the logging level you want to set from the list in the Logging section.