clustering and/or failover?

Started by Robert J. Sanford, Jr.over 24 years ago6 messagesgeneral
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#1Robert J. Sanford, Jr.
rsanford@nolimitsystems.com

thinking in the long-term for my project...

i'm looking at trying to set up two database servers with
some sort of clustering and/or failover that are talking
to a SAN. is this even feasible using postgres?

using ms sql server as an example (because that is what
my office is currently using) you can set up two database
servers that will check each other's heartbeat to see if
they are both up. if one goes down then the other takes
over responding to requests. you can also set up a
cluster that will have both machines responding to
requests concurrently.

with the data set up on a fibre channel raid box you
don't have to worry about replication, you just have to
make sure that the data is properly locked by each of
the servers (in the clustering example) so that no two
machines are updating the same data at the same time.

i am fairly certain that postgres cannot handle the
first example (heartbeats) but am wondering if it can
handle the second example where two instances are
hitting the same physical data store.

many thanks!

rjsjr

#2Tom Lane
tgl@sss.pgh.pa.us
In reply to: Robert J. Sanford, Jr. (#1)
Re: clustering and/or failover?

"Robert J. Sanford, Jr." <rsanford@nolimitsystems.com> writes:

... two instances are
hitting the same physical data store.

Nope. Don't even *think* about trying that.

regards, tom lane

#3Robert J. Sanford, Jr.
rsanford@nolimitsystems.com
In reply to: Tom Lane (#2)
RE: clustering and/or failover?

okay, the clustering option is out, what about a failover
option?

rjsjr

Show quoted text

-----Original Message-----
From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
Sent: Monday, August 20, 2001 7:57 PM
To: Robert J. Sanford, Jr.
Cc: pgsql-general@postgresql.org
Subject: Re: [GENERAL] clustering and/or failover?

"Robert J. Sanford, Jr." <rsanford@nolimitsystems.com> writes:

... two instances are
hitting the same physical data store.

Nope. Don't even *think* about trying that.

regards, tom lane

#4Jim Buttafuoco
jim@spectrumtelecorp.com
In reply to: Robert J. Sanford, Jr. (#3)
Re: clustering and/or failover?

Robert,

I have been running a "heartbeat" PG database cluster for a year now
using a shared SCSI bus. Yes the heartbeat software has to be careful
about when to mount the disk and on what system. But this seems to
work well (I did a lot of testing before putting into production.) This
is a pure master/standby cluster config.

Jim

thinking in the long-term for my project...

i'm looking at trying to set up two database servers with
some sort of clustering and/or failover that are talking
to a SAN. is this even feasible using postgres?

using ms sql server as an example (because that is what
my office is currently using) you can set up two database
servers that will check each other's heartbeat to see if
they are both up. if one goes down then the other takes
over responding to requests. you can also set up a
cluster that will have both machines responding to
requests concurrently.

with the data set up on a fibre channel raid box you
don't have to worry about replication, you just have to
make sure that the data is properly locked by each of
the servers (in the clustering example) so that no two
machines are updating the same data at the same time.

i am fairly certain that postgres cannot handle the
first example (heartbeats) but am wondering if it can
handle the second example where two instances are
hitting the same physical data store.

many thanks!

rjsjr

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Show quoted text
#5Robert J. Sanford, Jr.
rsanford@nolimitsystems.com
In reply to: Jim Buttafuoco (#4)
RE: clustering and/or failover?

what software are you running for this? where can i find it?

thanks!

rjsjr

Show quoted text

-----Original Message-----
From: pgsql-general-owner@postgresql.org
[mailto:pgsql-general-owner@postgresql.org]On Behalf Of Jim
Buttafuoco
Sent: Tuesday, August 21, 2001 6:53 AM
To: Robert J. Sanford, Jr.; pgsql-general@postgresql.org
Subject: Re: [GENERAL] clustering and/or failover?

Robert,

I have been running a "heartbeat" PG database cluster for
a year now using a shared SCSI bus. Yes the heartbeat
software has to be careful about when to mount the disk
and on what system. But this seems to work well (I did
a lot of testing before putting into production.) This
is a pure master/standby cluster config.

Jim

thinking in the long-term for my project...

i'm looking at trying to set up two database servers with
some sort of clustering and/or failover that are talking
to a SAN. is this even feasible using postgres?

using ms sql server as an example (because that is what
my office is currently using) you can set up two database
servers that will check each other's heartbeat to see if
they are both up. if one goes down then the other takes
over responding to requests. you can also set up a
cluster that will have both machines responding to
requests concurrently.

with the data set up on a fibre channel raid box you
don't have to worry about replication, you just have to
make sure that the data is properly locked by each of
the servers (in the clustering example) so that no two
machines are updating the same data at the same time.

i am fairly certain that postgres cannot handle the
first example (heartbeats) but am wondering if it can
handle the second example where two instances are
hitting the same physical data store.

many thanks!

rjsjr

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#6Jim Buttafuoco
jim@spectrumtelecorp.com
In reply to: Robert J. Sanford, Jr. (#5)
RE: clustering and/or failover?

http://linux-ha.org/ look for heartbeat.

Show quoted text

what software are you running for this? where can i find it?

thanks!

rjsjr

-----Original Message-----
From: pgsql-general-owner@postgresql.org
[mailto:pgsql-general-owner@postgresql.org]On Behalf Of Jim
Buttafuoco
Sent: Tuesday, August 21, 2001 6:53 AM
To: Robert J. Sanford, Jr.; pgsql-general@postgresql.org
Subject: Re: [GENERAL] clustering and/or failover?

Robert,

I have been running a "heartbeat" PG database cluster for
a year now using a shared SCSI bus. Yes the heartbeat
software has to be careful about when to mount the disk
and on what system. But this seems to work well (I did
a lot of testing before putting into production.) This
is a pure master/standby cluster config.

Jim

thinking in the long-term for my project...

i'm looking at trying to set up two database servers with
some sort of clustering and/or failover that are talking
to a SAN. is this even feasible using postgres?

using ms sql server as an example (because that is what
my office is currently using) you can set up two database
servers that will check each other's heartbeat to see if
they are both up. if one goes down then the other takes
over responding to requests. you can also set up a
cluster that will have both machines responding to
requests concurrently.

with the data set up on a fibre channel raid box you
don't have to worry about replication, you just have to
make sure that the data is properly locked by each of
the servers (in the clustering example) so that no two
machines are updating the same data at the same time.

i am fairly certain that postgres cannot handle the
first example (heartbeats) but am wondering if it can
handle the second example where two instances are
hitting the same physical data store.

many thanks!

rjsjr

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