Thanks Bonin.  Do you have totally 48 OSDs or there are 48 OSDs on each storage 
node?  Do you think "kernel.pid_max = 4194303" is reasonable since it increase 
a lot from the default OS setting.


Wei Cao (Buddy)

-----Original Message-----
From: Maciej Bonin [mailto:maciej.bo...@m247.com] 
Sent: Wednesday, June 11, 2014 10:07 PM
To: Cao, Buddy; ceph-users@lists.ceph.com
Subject: RE: pid_max value?

Hello,

The values we use are as follows:
# sysctl -p
net.ipv4.ip_local_port_range = 1024 65535 net.core.netdev_max_backlog = 30000 
net.core.somaxconn = 16384 net.ipv4.tcp_max_syn_backlog = 252144 
net.ipv4.tcp_max_tw_buckets = 360000 net.ipv4.tcp_fin_timeout = 3 
net.ipv4.tcp_max_orphans = 262144 net.ipv4.tcp_synack_retries = 2 
net.ipv4.tcp_syn_retries = 2 net.core.rmem_max = 8388608 net.core.wmem_max = 
8388608 net.core.rmem_default = 65536 net.core.wmem_default = 65536 
net.ipv4.tcp_rmem = 4096 87380 8388608 net.ipv4.tcp_wmem = 4096 65536 8388608 
net.ipv4.tcp_mem = 8388608 8388608 8388608 net.ipv4.route.flush = 1 
kernel.pid_max = 4194303

The timeouts don't really make sense without tw reuse/recycling but we found 
increasing the max and letting the old ones hang gives better performance.
Somaxconn was the most important value we had to increase as with 3 mons, 3 
storage nodes, 3 vm hypervisors, 16vms and 48 OSDs we've started running into 
major problems with servers dying left and right.
Most of those values are lifted from some openstack python script IIRC, please 
let us know if you find a more efficient/stable configuration, however we're 
quite happy with this one.

Regards,
Maciej Bonin
Systems Engineer | M247 Limited
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From: ceph-users [mailto:ceph-users-boun...@lists.ceph.com] On Behalf Of Cao, 
Buddy
Sent: 11 June 2014 15:00
To: ceph-users@lists.ceph.com
Subject: [ceph-users] pid_max value?

Hi, what is the recommended value for /proc/sys/kernel/pid_max? Is 32768 enough 
for Ceph cluster with 4 nodes (40 1T OSDs on each node)? My ceph node already 
run into "create thread fail" problem in osd log which root cause at pid_max.


Wei Cao (Buddy)

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