Page 1 of 1

Single file size exceeded 15 Terabytes

Posted: Wed Aug 28, 2019 5:09 pm
by ruimota
Hello,

One of our storage NAS QNAP got one file that grow up to 15,5 Terabytes in size.

After some research it seems that the maximum single file size for EXT4 is 15 TB.

Couldn't find any oficial information from QNAP regarding maximum single file size, so i am searching for help.

The main questions are:
1) Whats the real maximum single file size for QNAP NAS (TVS-871U-RP FW 4.3.6.0993) ?
2) If it exceeds the maximum data (file) wild be discarded or prevented access to it?

Currently that single file size is increasing but at a lower rate and i am trying to avoid the loss of this big file.

Any info about this limits would be a precious help.

Thanks,

RM

Re: Single file size exceeded 15 Terabytes

Posted: Thu Aug 29, 2019 9:55 am
by OneCD
ruimota wrote:
Wed Aug 28, 2019 5:09 pm
One of our storage NAS QNAP got one file that grow up to 15,5 Terabytes in size.
Windows runtime error log? :wink:
ruimota wrote:
Wed Aug 28, 2019 5:09 pm
After some research it seems that the maximum single file size for EXT4 is 15 TB.
With the QTS Linux kernel and hardware it's designed for, the maximum single file-size is 16TiB. This limit is determined (in-part) by the memory page-size (4096 bytes), and is hardcoded into the Linux kernel. This size limit can be overcome, but would require some kernel customisation.
ruimota wrote:
Wed Aug 28, 2019 5:09 pm
2) If it exceeds the maximum data (file) wild be discarded or prevented access to it?
Sorry, I don't know. But it would be interesting to see. My guess is there would be a slow crash. :lol:
ruimota wrote:
Wed Aug 28, 2019 5:09 pm
Currently that single file size is increasing but at a lower rate and i am trying to avoid the loss of this big file.
I've got to ask - why do you have a single file of 15.5TB?

Re: Single file size exceeded 15 Terabytes

Posted: Thu Aug 29, 2019 9:31 pm
by Toxic17
OneCD wrote:
Thu Aug 29, 2019 9:55 am
I've got to ask - why do you have a single file of 15.5TB?
Indeed, how is this file going to be read or opened? lol

Re: Single file size exceeded 15 Terabytes

Posted: Thu Aug 29, 2019 10:26 pm
by OneCD
Toxic17 wrote:
Thu Aug 29, 2019 9:31 pm
Indeed, how is this file going to be read or opened? lol
My guess is: very carefully. :DD

Re: Single file size exceeded 15 Terabytes

Posted: Fri Aug 30, 2019 7:13 am
by ruimota
Hi,

The size of the file is increasing (at a slow pace) and the software process behind it...is running fine.

I guess that if and when this file hits 16 Terabytes, QNAP Storage EXT4 will colapse.

Since the software process behind it is limited to 100 Terabytes, and data volume has 25 Terabytes capacity...i will wait to see what happens 8) .

Took an image from File Station, maybe thats something unusual to see in Storage QNAP.

Thanks for the reply and info.

RM

Re: Single file size exceeded 15 Terabytes

Posted: Fri Aug 30, 2019 7:16 am
by OneCD
What's in that file? It's not a virtual-machine image, is it?

Re: Single file size exceeded 15 Terabytes

Posted: Fri Aug 30, 2019 4:25 pm
by Toxic17
OneCD wrote:
Fri Aug 30, 2019 7:16 am
What's in that file? It's not a virtual-machine image, is it?
maybe a Virtual image with a ton of vSphere snapshots perhaps?