Re: [ceph-users] Some Questions about using ceph with VMware

[Florian Krauß]

Thank you Greg, thank you Kenneth,

i have enabled ntp now and the clock skew is getting smaller and it’s gone 
after a while, so everything is fine now.
I already thought the virtual Disks could slow down things, now i know it for 
sure.
My last question (for now): Is there any difference between rbd’s and a mounted 
cephFS concerning of the performance?

Thank you in advance,
Florian
Am 13.03.2014 um 03:36 schrieb kenneth kenn...@apolloglobal.net:

 On 3/12/2014 6:24 PM, Florian Krauß wrote:
 Hello everyone,
 
 this is the first time i ever write to a mailing list, please be patient 
 with me (especially for my poor english)…
 Im trying to reach my Bachelors Degree in Computer Science, Im doing a 
 Project which involves ceph.
 I’am able to setup a ceph Cluster, but there are a few things i can’t Figure 
 out…
 
 As I’am setting up the cluster with virtual machines im facing a little 
 Problem:
 clock skew: every time i reboot on node a clock skew is detected. If i 
 restart the Monitor on which the clock skew is detected the Problem is gone. 
 But this is not what i want to show in my presentation. I already enabled 
 the VMware tools, but the Problem persists. Does it make more sense to 
 enable NTP?
 You'll most likely need to setup NTP. I don't know of any better way to sync 
 clocks so be sure to install NTP on ceph nodes. You should setup a local NTP 
 server on your lan so that latency is very small
 
 Are there any performance Issues to expect if i use a drive with 
 ceph-disk-prepare (or activate)  /dev/sdb directly ?
 
 Are there any (big) performance Issues to expect using these virtual drives 
 instead of „real“ drives?
 Yes, virtual machine hard drives can be slower than hardware drives so 
 performance may be slower.
 
 Kind regards
 
 Florian
 ___
 ceph-users mailing list
 ceph-users@lists.ceph.com
 http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
 
 ___
 ceph-users mailing list
 ceph-users@lists.ceph.com
 http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com

___
ceph-users mailing list
ceph-users@lists.ceph.com
http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com

[ceph-users] Some Questions about using ceph with VMware

[Florian Krauß]

Hello everyone,

this is the first time i ever write to a mailing list, please be patient with 
me (especially for my poor english)…
Im trying to reach my Bachelors Degree in Computer Science, Im doing a Project 
which involves ceph.
I’am able to setup a ceph Cluster, but there are a few things i can’t Figure 
out…

As I’am setting up the cluster with virtual machines im facing a little Problem:
clock skew: every time i reboot on node a clock skew is detected. If i restart 
the Monitor on which the clock skew is detected the Problem is gone. But this 
is not what i want to show in my presentation. I already enabled the VMware 
tools, but the Problem persists. Does it make more sense to enable NTP?

Are there any performance Issues to expect if i use a drive with 
ceph-disk-prepare (or activate)  /dev/sdb directly ?

Are there any (big) performance Issues to expect using these virtual drives 
instead of „real“ drives?

Kind regards

Florian
___
ceph-users mailing list
ceph-users@lists.ceph.com
http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com