[[!comment format=mdwn
 username="yarikoptic"
 avatar="http://cdn.libravatar.org/avatar/f11e9c84cb18d26a1748c33b48c924b4"
 subject="comment 8"
 date="2022-05-31T19:07:59Z"
 content="""
Hi Joey -- thanks for digging all that up!  On my laptop I also use BTRFS (on top of dm encrypted volume) and always thought to check why `notmuch new` running at the end of offlineimap for me at times holds the entire laptop \"stalled\" for a few seconds.  I think you gave me the answer!  Following [this article](https://wiki.tnonline.net/w/Btrfs/Defrag) and defragmented `.glass` files under `~/Maildir/.notmuch/xapian` . Let's see now in the long run if I encounter similar stalling ;)

But I am not yet entirely sure if it really answers the \"total stall\" situation -- slow should still work.

FWIW -- I have checked in two repositories which were mentioned in this issue, in one (000233) the `keysdb/db` was ok -- just 30 refs, but the 000026 (a heavy beast ;)) had 2994:

```
drogon:/mnt/backup/dandi/dandisets/000026/.git/annex# /usr/sbin/compsize keysdb/db 
Processed 1 file, 2643 regular extents (2994 refs), 0 inline.
Type       Perc     Disk Usage   Uncompressed Referenced  
TOTAL       98%       20M          20M          14M       
none       100%       19M          19M          13M       
lzo         46%      352K         752K         400K 
```
FWIW I defraged it into 1 ref.  And then did the `chattr +C` on all repos I have there so far.  Let's see if that anyhow helps.

PS Have been using BTRFS on that server and smaug for almost 10 years now and had thousands of git annex repos... I guess these particular ones are pushing some limits  ;)
"""]]
