gmane.linux.region.israel

Amos Shapira | 22 Sep 11:57

MySQL over DRBD (was: Re: Clustering/Failover Project)

2008/9/22 Oleg Goldshmidt <pub@...>:
> Noam Rathaus <noamr@...> writes:
>
>> I'm also not interested in replies telling me there's a project that
>> does exactly that (and only requires a few tiny customizations that
>> will take days).
>
> Well, how about a couple of hours, including RTFM? LinuxHA (heartbeat,
> http://www.linux-ha.org) + DRBD (http://www.drbd.org,
> http://linux-ha.org/DRBD) is the most common linux HA solution, works
> great with MySQL (http://www.mysql.com/products/enterprise/drbd.html),
> comes with most linux distros [1,2], and thus is likely already
> installed on your system.

(I changed the subject since this is about replying to Oleg, not
within the scope of the original post).

We are using MySQL over DRBD mostly because I had to set it up in a
hurry and we were already using DRBD for PostgresQL and other files.

BUT now that we are finally moving from DNS-based fail-over (due to
lack of Virtual IP support in the hosting product we originally had)
to Virtual-IP (using Linux Virtual Server) we see how MySQL
master-master replication (using simple two-sided replication, e.g.
http://www.howtoforge.com/mysql-5-master-master-replication-fedora-8,
NOT the "MySQL Cluster" product which last time I read about it it
sounded like a bad joke) would benefit us -
1. It means that fail-over time will be virtually zero (compared to a
few seconds to bring up the secondary)
2. It means that we can take advantage of both MySQL servers in

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Oleg Goldshmidt | 22 Sep 15:55

Re: MySQL over DRBD (was: Re: Clustering/Failover Project)

"Amos Shapira" <amos.shapira@...> writes:

> BUT now that we are finally moving from DNS-based fail-over (due to
> lack of Virtual IP support in the hosting product we originally had)
> to Virtual-IP (using Linux Virtual Server) we see how MySQL
> master-master replication (using simple two-sided replication, e.g.
> http://www.howtoforge.com/mysql-5-master-master-replication-fedora-8,
> NOT the "MySQL Cluster" product which last time I read about it it
> sounded like a bad joke) would benefit us -
> 1. It means that fail-over time will be virtually zero (compared to a
> few seconds to bring up the secondary)
> 2. It means that we can take advantage of both MySQL servers in
> parallel - for higher capacity

It looks like you are also interested in load balancing / scalability
and are looking for active/active failover as a part of that. AFAIK,
LinuxHA has active/active mode, but I have never used it. From Noam's
description it seems that active/passive is what he is looking for.

>> [2] RedHat is the only exception I know of, I suppose because they
>>    have their own clustering product - of course RPMs are there.
>
> Exception to what? Linux-HA and DRBD comes packaged in CentOS 5 and we
> have all software from rpm's, we didn't have to compile anything.

RPMs are there, but AFAIK they are not included by default in RHEL
(the "RedHat" we, as a commercial company, normally deal with, as
opposed to CentOS). Other distros (including, e.g., SLES) have LinuxHA
in by default. We have it here on RHEL, actually it was the first
platform we tried it on and it was up and running in no time,

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Amos Shapira | 23 Sep 07:24

Re: MySQL over DRBD (was: Re: Clustering/Failover Project)

Yes, we also want to take advantage of the option to expand capacity,
but even just for purposes of smoother fail-over (i.e. shorter down
time, actually zero down time as far as the server's availability is
concerned) I see the advantage of db-level replication over DRBD.

(sorry for top posting. Mail client limitation)

--Amos

On 9/22/08, Oleg Goldshmidt <pub@...> wrote:
> "Amos Shapira" <amos.shapira@...> writes:
>
>> BUT now that we are finally moving from DNS-based fail-over (due to
>> lack of Virtual IP support in the hosting product we originally had)
>> to Virtual-IP (using Linux Virtual Server) we see how MySQL
>> master-master replication (using simple two-sided replication, e.g.
>> http://www.howtoforge.com/mysql-5-master-master-replication-fedora-8,
>> NOT the "MySQL Cluster" product which last time I read about it it
>> sounded like a bad joke) would benefit us -
>> 1. It means that fail-over time will be virtually zero (compared to a
>> few seconds to bring up the secondary)
>> 2. It means that we can take advantage of both MySQL servers in
>> parallel - for higher capacity
>
> It looks like you are also interested in load balancing / scalability
> and are looking for active/active failover as a part of that. AFAIK,
> LinuxHA has active/active mode, but I have never used it. From Noam's
> description it seems that active/passive is what he is looking for.
>
>>> [2] RedHat is the only exception I know of, I suppose because they

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