Hi Guillaume, Yes, it helps. Thanks! I can log these every hour (say) and plot the curve over a week to get an idea of rate and its variability.
Tom From: Guillaume Lefranc <[email protected]> Date: Saturday, December 5, 2015 at 12:57 PM To: Tom Worster <[email protected]>, Bertrand Caplet <[email protected]>, maria-discuss email list <[email protected]> Subject: Re: [Maria-discuss] Most reliable SST (or IST ?) method for MariaDB Cluster Hi Tom, Use the wsrep_replicated_bytes and wsrep_received_bytes status variables. The sum of those two variables will give you the total bytes written to gcache. By using a derivative function you should be able to figure out the write rate. Hope this helps, On Sat, Dec 5, 2015 at 6:46 PM Tom Worster <[email protected]> wrote: > Hi Guillaume, > > What variable(s) should we monitor to estimate the rate at which gcache is > written? or to otherwise estimate how far back a given gcache.size goes in > history? > > Tom > > > From: Maria-discuss > <[email protected]> on behalf of > Guillaume Lefranc <[email protected]> > Date: Saturday, December 5, 2015 at 10:23 AM > To: Bertrand Caplet <[email protected]>, maria-discuss email list > <[email protected]> > Subject: Re: [Maria-discuss] Most reliable SST (or IST ?) method for MariaDB > Cluster > > Hi Bertrand, > > You don't want your partitioned node to do SST, because IST is obviously > faster. > IST should always happen, unless the node has lost state (crash, inconsistent > data, etc) or the latest writeset is not found in the galera cache. > So, rule of thumb is to have a galera cache big enough, so it can hold the > latest writesets while your node is partitioned. > Galera cache (the name is a bit misleading, it's more like a binary log) is > just a file on disk, so the limitation is about disk space only. > Set it like this: wsrep_provider_options="gcache.size=5G" > > About xtrabackup methods. the legacy xtrabackup method should not be used > anymore, as it is deprecated because of many bugs/issue. > Use xtrabackup-v2 in all cases. You can improve the method by setting some > [xtrabackup] options in your my.cnf file, such as: > > # Enables compression, requires qpress package > compress > # Enables parallel transfers (n=number of threads) > parallel=n > > xtrabackup-v2 method does not lock the donor database while it is processing, > so it can be used for "hot" SST (on the contrary, rsync needs a global lock) > > Regards, > > On Sat, Dec 5, 2015 at 2:46 PM Bertrand Caplet <[email protected]> > wrote: >> Hi all, >> I'm using MariaDB Cluster with 3 servers and I often have split brain >> because of network. When a network split brain happen, only one node is >> disconnected. >> What is for you the best choice for SST or maybe IST method for this >> configuration ? (N.B.: I already tried rsync method but i'm not really >> satisfied with it). >> >> I have another question, I tried xtrabackup-v2 but it seems this method >> can't be use for bootstrapping while database is on. Does xtrabackup >> method can do this ? >> >> Regards, >> >> -- >> CHUNKZ.NET <http://CHUNKZ.NET> - script kiddie and computer technician >> Bertrand Caplet, Flers (FR) >> Feel free to send encrypted/signed messages >> Key ID: 37F70C30 >> GPG FP: 134A 4027 518B 5F4D D409 558D BA9B 7BF0 37F7 0C30 >> >> >> _______________________________________________ >> Mailing list: https://launchpad.net/~maria-discuss >> Post to : [email protected] >> Unsubscribe : https://launchpad.net/~maria-discuss >> More help : https://help.launchpad.net/ListHelp > -- > Guillaume Lefranc > Remote DBA Services Manager > MariaDB Corporation > _______________________________________________ Mailing list: > https://launchpad.net/~maria-discuss Post to : > [email protected] Unsubscribe : > https://launchpad.net/~maria-discuss More help : > https://help.launchpad.net/ListHelp -- Guillaume Lefranc Remote DBA Services Manager MariaDB Corporation
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