I've come up with a better name for the concept of file and directory
fragmentation which is, "Filesystem Entropy". Where, over time, an
active and volitile filesystem moves from an organized state to a
disorganized state resulting in backup difficulties.
Here are some stats which illustrate the issue:
First the development mail server:
==================================
(Jump frames, Nagle disabled and tcp_xmit_hiwat,tcp_recv_hiwat set to
2097152)
Small file workload (copy from zfs on iscsi network to local ufs
filesystem)
# zpool iostat 10
capacity operations bandwidth
pool used avail read write read write
---------- ----- ----- ----- ----- ----- -----
space 70.5G 29.0G 3 0 247K 59.7K
space 70.5G 29.0G 136 0 8.37M 0
space 70.5G 29.0G 115 0 6.31M 0
space 70.5G 29.0G 108 0 7.08M 0
space 70.5G 29.0G 105 0 3.72M 0
space 70.5G 29.0G 135 0 3.74M 0
space 70.5G 29.0G 155 0 6.09M 0
space 70.5G 29.0G 193 0 4.85M 0
space 70.5G 29.0G 142 0 5.73M 0
space 70.5G 29.0G 159 0 7.87M 0
Large File workload (cd and dvd iso's)
# zpool iostat 10
capacity operations bandwidth
pool used avail read write read write
---------- ----- ----- ----- ----- ----- -----
space 70.5G 29.0G 3 0 224K 59.8K
space 70.5G 29.0G 462 0 57.8M 0
space 70.5G 29.0G 427 0 53.5M 0
space 70.5G 29.0G 406 0 50.8M 0
space 70.5G 29.0G 430 0 53.8M 0
space 70.5G 29.0G 382 0 47.9M 0
The production mail server:
===========================
Mail system is running with 790 imap users logged in (low imap work
load).
Two backup streams are running.
Not using jumbo frames, nagle enabled, tcp_xmit_hiwat,tcp_recv_hiwat set
to 2097152
- we've never seen any effect of changing the iscsi transport
parameters
under this small file workload.
# zpool iostat 10
capacity operations bandwidth
pool used avail read write read write
---------- ----- ----- ----- ----- ----- -----
space 1.06T 955G 96 69 5.20M 2.69M
space 1.06T 955G 175 105 8.96M 2.22M
space 1.06T 955G 182 16 4.47M 546K
space 1.06T 955G 170 16 4.82M 1.85M
space 1.06T 955G 145 159 4.23M 3.19M
space 1.06T 955G 138 15 4.97M 92.7K
space 1.06T 955G 134 15 3.82M 1.71M
space 1.06T 955G 109 123 3.07M 3.08M
space 1.06T 955G 106 11 3.07M 1.34M
space 1.06T 955G 120 17 3.69M 1.74M
# prstat -mL
PID USERNAME USR SYS TRP TFL DFL LCK SLP LAT VCX ICX SCL SIG
PROCESS/LWPID
12438 root 12 6.9 0.0 0.0 0.0 0.0 81 0.1 508 84 4K 0 save/1
27399 cyrus 15 0.5 0.0 0.0 0.0 0.0 85 0.0 18 10 297 0 imapd/1
20230 root 3.9 8.0 0.0 0.0 0.0 0.0 88 0.1 393 33 2K 0 save/1
25913 root 0.5 3.3 0.0 0.0 0.0 0.0 96 0.0 22 2 1K 0 prstat/1
20495 cyrus 1.1 0.2 0.0 0.0 0.5 0.0 98 0.0 14 3 191 0 imapd/1
1051 cyrus 1.2 0.0 0.0 0.0 0.0 0.0 99 0.0 19 1 80 0 master/1
24350 cyrus 0.5 0.5 0.0 0.0 1.4 0.0 98 0.0 57 1 484 0 lmtpd/1
22645 cyrus 0.6 0.3 0.0 0.0 0.0 0.0 99 0.0 53 1 603 0 imapd/1
24904 cyrus 0.3 0.4 0.0 0.0 0.0 0.0 99 0.0 66 0 863 0 imapd/1
18139 cyrus 0.3 0.2 0.0 0.0 0.0 0.0 99 0.0 24 0 195 0 imapd/1
21459 cyrus 0.2 0.3 0.0 0.0 0.0 0.0 99 0.0 54 0 635 0 imapd/1
24891 cyrus 0.3 0.3 0.0 0.0 0.9 0.0 99 0.0 28 0 259 0 lmtpd/1
388 root 0.2 0.3 0.0 0.0 0.0 0.0 100 0.0 1 1 48 0
in.routed/1
21643 cyrus 0.2 0.3 0.0 0.0 0.2 0.0 99 0.0 49 7 540 0 imapd/1
18684 cyrus 0.2 0.3 0.0 0.0 0.0 0.0 100 0.0 48 1 544 0 imapd/1
25398 cyrus 0.2 0.2 0.0 0.0 0.0 0.0 100 0.0 47 0 466 0 pop3d/1
23724 cyrus 0.2 0.2 0.0 0.0 0.0 0.0 100 0.0 47 0 540 0 imapd/1
24909 cyrus 0.1 0.2 0.0 0.0 0.2 0.0 99 0.0 25 1 251 0 lmtpd/1
16317 cyrus 0.2 0.2 0.0 0.0 0.0 0.0 100 0.0 37 1 495 0 imapd/1
28243 cyrus 0.1 0.3 0.0 0.0 0.0 0.0 100 0.0 32 0 289 0 imapd/1
20097 cyrus 0.1 0.2 0.0 0.0 0.3 0.0 99 0.0 26 5 253 0 lmtpd/1
Total: 893 processes, 1125 lwps, load averages: 1.14, 1.16, 1.16
--
Ed
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