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Hello

After the backup is completed on the Linux Client server on which the File system agent is installed, the used memory cannot be returned.
Memory returns normally after the server power is restarted.
However, after the backup starts again and is complete, the memory used for the backup is not returned again.

 

The backup job for this server starts at 21:00 every day.

 

This is the amount of change in memory before and after the backup starts after the server power is rebooted.

 

After the backup is complete, the memory usage is as follows.

Memory usage for processes on that server.

 

The Linux OS for this server is Redhat 6.2 and the installed Commvault version is V10 SP15.

Hi, 
You should consider the possibilities of upgrading the CV to 11.24.XX at first place 

Having said that, please check for the following

  1. If SE Linux is enabled
  2. Since there vmtools (PID - 1756) in list, is there a possibility of backing up as VM
  3. If it needs to be executed as FS backup, there are possible locks which needs to be looked for

Hi, 
You should consider the possibilities of upgrading the CV to 11.24.XX at first place 

Having said that, please check for the following

  1. If SE Linux is enabled
  2. Since there vmtools (PID - 1756) in list, is there a possibility of backing up as VM
  3. If it needs to be executed as FS backup, there are possible locks which needs to be looked for

Hello.

Thank you for your reply.

Let me check what you said.

I'm sorry to add this, but I don't understand the contents of 3. So I'd appreciate it if you could tell me which lock to find.


Hi, 
You should consider the possibilities of upgrading the CV to 11.24.XX at first place 

Having said that, please check for the following

  1. If SE Linux is enabled
  2. Since there vmtools (PID - 1756) in list, is there a possibility of backing up as VM
  3. If it needs to be executed as FS backup, there are possible locks which needs to be looked for

Hello @Ramkumar Giridaran .

Thank you for your reply.

I will share the result of the confirmation.

1. SELinux is disabled.

2. This server is a VM server, but it is backed up by the Agent installation and is not included in the VM backup target.

3. I'm sorry. I don't understand this, so could you explain it again?


Its been a while since I worked with linux, but I was quite involved in the original Commvault HyperScale appliance launch.

I feel like with Linux memory is rarely returned to the free pool but used opportunistically for caching - especially to speed up file access (which is exactly what a backup will cause the kernel to do).

Free = wasted, 100% unused. If the memory is being used to cache files to improve performance, that is better than having a heap of free memory that is providing absolutely no benefit.

Its a complex topic with a lot of articles - but unless you can link it to a performance issue I think this is totally expected. 

https://haydenjames.io/measure-web-server-memory-usage-correctly/

The command ‘free’ will never let you down!

From the Linux command line, using the free command or (or free -m or free -h) will often reveal that you are “using” more memory, thank you think! See this example below from Red Hat’s docs:

$ free              total       used        free    shared    buffers    cachedMem:        4040360    4012200       28160         0     176628   3571348-/+ buffers/cache:      264224     3776136Swap:       4200956      12184     4188772

Notice there’s 28160KB “free.” However, below that line, look at how much memory has been consumed by buffers and cache! Linux always tries to use memory first to speed up disk operations by using available memory for buffers (file system metadata) and cache (pages with actual contents of files or block devices). This helps the system to run faster because disk information is already in memory which saves I/O operations. If more space is required, Linux will free up the buffers and cache to yield memory for the applications. If there’s not enough “free” space, then the cache will be saved (swapped) to disk. It would be wise to monitor this, keep swap and cache contention within an acceptable range that does not affect performance. – Source: Red Hat.