[FreeBSD] kern.ipc.nmbclusters て

増やすのはブート時でなくて
起動後でもできるようになってたのか。。
いつから？ 6.2 でもできた。。

% sysctl kern.ipc.nmbclusters
kern.ipc.nmbclusters: 12864
% sudo sysctl kern.ipc.nmbclusters=32768
Password:
kern.ipc.nmbclusters: 12864 -> 32768
% sudo sysctl kern.ipc.nmbclusters=65536
kern.ipc.nmbclusters: 32768 -> 65536

% sudo sysctl kern.ipc.nmbclusters=32768
kern.ipc.nmbclusters: 65536
sysctl: kern.ipc.nmbclusters: Invalid argument


% netstat -m
69/201/270 mbufs in use (current/cache/total)
64/70/134/65536 mbuf clusters in use (current/cache/total/max)
64/64 mbuf+clusters out of packet secondary zone in use (current/cache)
0/2/2/0 4k (page size) jumbo clusters in use (current/cache/total/max)
0/0/0/0 9k jumbo clusters in use (current/cache/total/max)
0/0/0/0 16k jumbo clusters in use (current/cache/total/max)
145K/198K/343K bytes allocated to network (current/cache/total)
0/0/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters)
0/0/0 requests for jumbo clusters denied (4k/9k/16k)
0/4/3472 sfbufs in use (current/peak/max)
0 requests for sfbufs denied
0 requests for sfbufs delayed
0 requests for I/O initiated by sendfile
0 calls to protocol drain routines


一方、Mac OS X(というより Darwin ?)はできない。read only。

% sudo sysctl -w kern.ipc.nmbclusters=65536
sysctl: oid 'kern.ipc.nmbclusters' is read only


どうもぐぐってここみられてるらしいので追記しとくか:
関連)
Tuning Kernel Limits
Performance - Varnish