[Glass] Fwd: Backup procedure

Otto Behrens via Glass glass at lists.gemtalksystems.com
Thu Jul 28 23:27:29 PDT 2016

Seems as if my mail went directly to Dario, so just copying it here if
anyone is interested.

---------- Forwarded message ----------
From: Otto Behrens <otto at finworks.biz>
Date: Fri, Jul 29, 2016 at 8:26 AM
Subject: Re: [Glass] Backup procedure
To: Trussardi Dario Romano <dario.trussardi at tiscali.it>

Hi Dario,

> Regarding risk of losing data on system restart ... you should already be
> keeping copies of your backup files and tranlogs on a separate system, so
> that if you lose a disk, you have fairly recent copies of both ... if you
> are concerned about losing as little data as possible, you might think about
> copy tranlogs to a separate machine several times a day ...

Every day, we run SystemRepository fullBackupCompressedTo:, and then
scp the file to a backup server

> A)  I need a external script  for create the new tranlog  every hour with
> the  System class >> startNewLog.
> In general i have some methods to perform at regular time and data but i
> don't understand if i can schedule it directly into the gemstone,
> or if i need external scripts call by Crontab?

You can do this from cron. But GemStone has settings to control when
to write tranlogs, if you require more frequent logs.

We do not do this, we use the hot standby. See below.

> B) On LAN i have a Windows system for perform ftp copy from the Gemstone
> server to the backup system.
> ( i use the Cobian program )
> Now i think to setup the incremental  ftp copy of the  /tranlogs  server
> directory.
> But how does the ftp command by copying the online tranlog ?
> Can create problematic on the server?

If you do startNewLog from your cron script, it tells you which log
was created. You can then safely copy the previous logs away.

Again, we do not do this, we rely on the standby.

> C) Link to my last email :   [Glass] Integrity of the system
> I read about Warm and Hot Standbys

Yes, we use this. LogSender on production and LogReceiver on standby.

> Is not possible have the " online copy " of the current  tranlog on the
> backup system ?

The hot standby system does that. As log entries are written on your
production system, they are copied across to your standby system (into
the same tranlog file).

> Where for online copy i think the copy at the last transaction ( update at
> the last minute?! ) on the server.

Yes, the logsender / logreceiver updates almost as it happens.

> If this would be possible, when the server crash, on the backup system i
> found the tranlog update to the latest transactions.
>  Is not bad?

You can do this, yes. We have recovered from the hot standby before.

> Am I asking too much?

Nope, it is there.

Managing the eco-system of production and hot standby is a bit of
work. This is to ensure that it actually *is* running. For us, it is
not enough to just start the logsender and logreceiver. We want to be
sure that it is working. So, on our standby server, we parse the log
output and log for signs of recent syncing activity. This is a ruby
script. So, if you'd like to have a look at the scripts, let me know.

Also, we restore the overnight backup and restart the syncing process
on the standby machine every day. Strictly speaking, you don't need to
do this every day (although it's advisable to do on some frequency, I
think). We do this to keep the extent small and to reduce the number
of transaction logs we need.


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