On 11/16/2018 03:51 AM, Nikolay Borisov wrote:
On 15.11.18 г. 20:39 ч., Juan Alberto Cirez wrote:
Is BTRFS mature enough to be deployed on a production system to underpin
the storage layer of a 16+ ipcameras-based NVR (or VMS if you prefer)?
Based on our limited experience with BTRFS (1+ year) under the above
scenario the answer seems to be no; but I wanted you ask the community
at large for their experience before making a final decision to hold off
on deploying BTRFS on production systems.
Let us be clear: We think BTRFS has great potential, and as it matures
we will continue to watch its progress, so that at some future point we
can return to using it.
The issue has been the myriad of problems we have encountered when
deploying BTRFS as the storage fs for the NVR/VMS in cases were the
camera count exceeds 10: Corrupted file systems, sudden read-only file
system, re-balance kernel panics, broken partitions, etc.
What version of the file system, how many of those issues (if any) have
you reported to the upstream mailing list? I don't remember seeing any
reports from you.
One specific case saw the btrfs drive pool mounted under the /var
partition so that upon installation the btrfs pool contained all files
under /var; /lib/mysql as well as the video storage. Needless to say
this was a catastrophe...
BTRFS is not suitable for random workloads, such as databases for
example. In those cases it's recommended, at the very least, to disable
COW on the database files. Note, disabling CoW doesn't preclude you from
creating snapshots, it just means that not every 4k write (for example)
will result in a CoW operation.
At the other end of the spectrum is a use case where ONLY the video
storage was on the btrfs pool; but in that case, the btrfs pool became
read-only suddenly and would not re-mount as rw despite all the recovery
trick btrfs-tools could throw at it. This, of course prevented the
NVR/VMS from recording any footage.
Again, you give absolutely no information about how you have configured
the filesystem or versions of the software used.
So, again, the question is: is BTRFS mature enough to be used in such
use case and if so, what approach can be used to mitigate such issues.
And..
What is the blocksize used by the application to write into btrfs?
And what type of write IO? async, directio or fsync?
Thanks, Anand
Thank you all for your assistance
-Ryan-
