Observations: File Size & Link attachments

Forgot to add… I am also in favor of some way to have files automatically placed in separate folders but instead of time stamp folder names I would suggest folder names based on the senders email address or perhaps better, time stamped and email address like Joe@gmail.com_20190419_1405.

Had an interesting occurrence today. A rather impatient user that wanted to upload several hundred pics, (I think) perhaps dragged the same set of files to the form more than once with two results:
1) I was told the site froze
2) On the backend I found there were multiple duplicates like c44, c44-1, c44-2, c44-3, etc

I looked at the cpanel back end and found the I/O was hitting 100% for a bit.

As a test I went and uploaded (or tried) 310 photos with sizes ranging from aprox .5MB to 2.5MB, total upload 409MB.
1) The form page froze after abut 15 seconds meaning all progress bars stopped running
2) Trying to open the site in a new tab took several minutes, spinning icon.
3) Looking at the upload folder in the backend via FTP showed only 3 files were uploaded after about 10 minutes.

cPanel did not show any I/O issues.

Ohhhh, interesting… After about 15 min about 15 of the progress bars were replaced with:
“The uploaded file exceeds the maximum upload size of your server.”

FYI, the shortcode in the contact form is:
[mfile Upload-Files limit:51048576 max-file:500]

I thought I had set a high enough limit but, guess not so I changed it to:
[mfile Upload-Files limit:1000000000 max-file:500]

I ran the same test with the same batch of photos and had similar results:
1) The form page quickly froze meaning all progress bars stopped running
2) However, opening the site in a new tab was OK.
3) Looking at the upload folder in the backend via FTP showed only 2 files were uploaded after about 5 minutes.

After about 10 min the upload form progress bars for about 22 items were replaced with the same maximum upload size error.
Looking again at the upload folder in the backend showed 18 files were uploaded.

Checking the cpanel again and I/O Usage was at 100%
and physical Memory Usage was at 98.65%.

Some minutes later more of the progress bars had been replaced with the error.
Only two progress bars indicated 100%

As a reference, uploading the same 310 photos via FTP takes about 5 minutes and does not cause any cpanel I/O or memory errors.

Thanks Glen,

I do realize FTP access is inherently different. I noted it just to say that basic I/O was not an issue.

I have looked at a few things and indeed, what I was pushing was way way over the top however, even when well under the thresholds I am aware of, the same issues occur.
As I understand it, the key php.ini settings are post_max_size, upload_max_filesize and memory_limit.
The current settings are:
post_max_size = 128M
upload_max_filesize = 128M
memory_limit = 512M
I suppose max_execution_time and max_input_time could also be a factor. The current settings are:
max_execution_time = 30
max_input_time = 60
However, I would say that when the form freezes it occurs after about 10 seconds so I presume neither of these is being overrun.

I dropped the file count to 50 with a combined size of 71.6MB (75,138,072 bytes), the form freezes.
I dropped the file count to 25, combined size of 35MB and the form did not freeze however, something was still off in the background. All the progress bars completed very quickly but it took several minutes before anything appeared in the upload folder and about 10 minutes elapsed before I could successfully send the email.
To help reduce front-end confusion I changed the Contact 7 error message to: “Your upload is still being processed. Please wait a few minutes and try to resend your message again.

Still love the plugin and presume the issues are server side and only indirectly associated to the plugin but it would be nice to know the actual limits and what the delays are.