Re: very slow "btrfs dev delete" 3x6Tb, 7Tb of data

[Leszek Dubiel <leszek@xxxxxxxxx>]

I have made some measurements in case someone has the same profile on 
his server.




=============
=== BTRFS ===

This is the same server "wawel" that was discussed above on
slow "btrfs delete" and "btrfs balance".

I must admit that BTRFS is much faster these days than ReiserFs.
See ReiserFs below.



** 51 minutes to list 11 million files:

root@wawel:/mnt/root/orion# time find > list_of_files
real    51m14,611s
user    0m30,487s
sys     2m23,520s

root@wawel:/mnt/root/orion# wc -l list_of_files
11439162 list_of_files



** 86 min to check size of files

root@wawel:/mnt/root/orion# time du -abx > disk_usage
real    86m42,328s
user    0m47,225s
sys     7m13,320s

root@wawel:/mnt/root/orion# wc -l disk_usage
11438206 disk_usage



** 45 minutes to read half million files, 50GB of data

root@wawel:/mnt/root/orion# egrep 'root/Omega/Domains/Zakupy' disk_usage 
| wc -l
476499

root@wawel:/mnt/root/orion# egrep 'root/Omega/Domains/Zakupy$' disk_usage
49154713130    ./root/Omega/Domains/Zakupy

root@wawel:/mnt/root/orion# time find root/Omega/Domains/Zakupy/ -type f 
-print0 | xargs -0r wc > word_count
real    45m11,398s
user    32m22,395s
sys     0m22,657s



** 21 min to copy 50Gb

root@wawel:/mnt/root/orion# time cp -a root/Omega/Domains/Zakupy/ tempcopy
real    21m36,030s
user    0m9,553s
sys     2m47,038s


** remove is very fast

root@wawel:/mnt/root/orion# time rm -r tempcopy
real    0m39,952s
user    0m0,359s
sys     0m9,985s



** number of files by given size

root@wawel:/mnt/root/orion# cat disk_usage | perl -MData::Dumper -e 
'$Data::Dumper::Sortkeys = 1; while (<>) { chomp; my ($byt, $nam) = 
split /\t/, $_, -1; if (index("$las/", $nam) == 0) { $dir++; } else { 
$filtot++; for $p (1 .. 99) { if ($byt < 10 ** $p) { $fil{"num of files 
size <10^$p"}++; last; } } }; $las = $nam; }; print "\ndirectories: 
$dir\ntotal num of files: $filtot\n", "\nnumber of files grouped by 
size: \n", Dumper(\%fil) '

directories: 1314246
total num of files: 10123960

number of files grouped by size:
$VAR1 = {
          'num of files size <10^1' => 3325886,
          'num of files size <10^2' => 3709276,
          'num of files size <10^3' => 789852,
          'num of files size <10^4' => 1085927,
          'num of files size <10^5' => 650571,
          'num of files size <10^6' => 438717,
          'num of files size <10^7' => 116757,
          'num of files size <10^8' => 6638,
          'num of files size <10^9' => 323
          'num of files size <10^10' => 13,
        };



** disk speed

root@wawel:/mnt/root/orion# hdparm -t /dev/sda
/dev/sda:
 Timing buffered disk reads: 680 MB in  3.01 seconds = 226.14 MB/sec





================
=== REISERFS ===

ReiserFs is much slower:

root@gamma:/mnt/sdb1/orion2# time find > list_of_files
real    111m49,529s
user    0m28,665s
sys     1m3,576s

root@gamma:/mnt/sdb1/orion2# wc -l list_of_files
11329332 list_of_files

root@gamma:/mnt/sdb1/orion2# time du -abx > disk_usage
real    198m43,813s
user    0m53,501s
sys     3m38,447s

root@gamma:/mnt/sdb1/orion2# hdparm -t /dev/sdb
/dev/sdb:
 Timing buffered disk reads: 534 MB in  3.00 seconds = 177.77 MB/sec