Now I want to use Corosync + Pacemaker in iscsi target
[cid:image002.png@01D1091A.AEFC8740]
iSCSI Active/Passive With Virtual IPs
Server1 accesses the two targets/GWs one at a time
through one or more Virtual IPs. The server1 use oracle.
If the active target goes down, corosync/pacemaker will
activate the passive target.
IPMI fencing, one of the most common types, takes a few seconds.
I feel that this time is too long,
Can it guarantee my business is not interrupted?
On 16/10/15 05:20 AM, Shilu wrote:
> When master is down, can the time of switching backup to master be
> shorter than a second?
Not safely, no.
In HA, if a node is declared dead, it needs to be fenced/stonith'ed before its services are recovered. Not doing this can lead to a split-brain. The process of fencing a node takes time; Exactly how much depends on the device or method you are using. IPMI fencing, one of the most common types, takes a few seconds.
Also, if you shorten the time it takes to declare a node dead, you increase the chance of having a node declared dead when it's not.
-------------------------------------------------------------------------------------------------------------------------------------
????????????????????????????????????????
????????????????????????????????????????
????????????????????????????????????????
???
This e-mail and its attachments contain confidential information from H3C, which is
intended only for the person or entity whose address is listed above. Any use of the
information contained herein in any way (including, but not limited to, total or partial
disclosure, reproduction, or dissemination) by persons other than the intended
recipient(s) is prohibited. If you receive this e-mail in error, please notify the sender
by phone or email immediately and delete it!
[cid:image002.png@01D1091A.AEFC8740]
iSCSI Active/Passive With Virtual IPs
Server1 accesses the two targets/GWs one at a time
through one or more Virtual IPs. The server1 use oracle.
If the active target goes down, corosync/pacemaker will
activate the passive target.
IPMI fencing, one of the most common types, takes a few seconds.
I feel that this time is too long,
Can it guarantee my business is not interrupted?
On 16/10/15 05:20 AM, Shilu wrote:
> When master is down, can the time of switching backup to master be
> shorter than a second?
Not safely, no.
In HA, if a node is declared dead, it needs to be fenced/stonith'ed before its services are recovered. Not doing this can lead to a split-brain. The process of fencing a node takes time; Exactly how much depends on the device or method you are using. IPMI fencing, one of the most common types, takes a few seconds.
Also, if you shorten the time it takes to declare a node dead, you increase the chance of having a node declared dead when it's not.
-------------------------------------------------------------------------------------------------------------------------------------
????????????????????????????????????????
????????????????????????????????????????
????????????????????????????????????????
???
This e-mail and its attachments contain confidential information from H3C, which is
intended only for the person or entity whose address is listed above. Any use of the
information contained herein in any way (including, but not limited to, total or partial
disclosure, reproduction, or dissemination) by persons other than the intended
recipient(s) is prohibited. If you receive this e-mail in error, please notify the sender
by phone or email immediately and delete it!
Attached Files:
-
image002.png (20.2 KB)