[squid-users] File descriptor usage for squid statistics

[Alex Rousskov]

On 2025-01-06 00:37, Jonathan Lee wrote:

> Can you please help I have noticed for a long time under information 
> page that Store Disk Files Open is a lot of the times showing 0
> 
> Is this of concern?

If your Squid is not configured to use a cache_dir, then seeing zero 
Store Disk files open is OK.

If your Squid is configured to use a rock cache_dir, then seeing zero or 
very few Store Disk files open is usually OK.

If your Squid is more-or-less idle at mgr:info query time, then seeing 
zero Store Disk files open is usually OK.


> I thought I should email and ask as I have not found 
> any information that gives clarity on what this section of the status 
> page relates to. 

This low-level statistics shows a very approximate counter of files open 
for the purpose related to managing responses in a cache_dir storage. 
The exact definitions of "file", "open", and "storage" vary from one 
cache_dir type to another.

N.B. All(?) other lines in "File descriptor usage for squid" section 
include network socket descriptors (and not just disk file descriptors).


If you can add this (or better) info to Squid wiki, please do.


> I have seen it at 1 at times however it shows failed to 
> parse headers or something also.

Those events are probably unrelated, but I cannot be sure without seeing 
the exact failure messages.


HTH,

Alex.


> File descriptor usage for squid:
> 	Maximum number of file descriptors:   97578
> 	Largest file desc currently in use:   1452
> 	Number of file desc currently in use: 1215
> 	Files queued for open:                   0
> 	Available number of file descriptors: 96363
> 	Reserved number of file descriptors:   100
> 	Store Disk files open:                   0
> Internal Data Structures:
> 	 17774 StoreEntries
> 	  4091 StoreEntries with MemObjects
> 	  4032 Hot Object Cache Items
> 	 17715 on-disk objects
>