dunno about any special tools, but misusing a mysql database could be a good check for this. unplug/reset your device while inserts into the db are ongoing (dont forget to use innodb for the tables). unplug / reset your device, boot it up again and take a look into the mysql log. theres a good chance that innodb gets wrecked... sure, this is not perfect. but could be a impressive test if it ends like i think. make sure your mysql instance is configured to be "safe": http://dev.mysql.com/doc/refman/5.1/en/innodb-parameters.html#sysvar_innodb_flush_method http://dev.mysql.com/doc/refman/5.1/en/innodb-parameters.html#sysvar_innodb_flush_log_at_trx_commit and enable binlogs + sync binlogs or in other words: make it as slow as possible :p On Sun, Oct 12, 2014 at 4:07 PM, Ivan Baldo <ibaldo@xxxxxxxxxxxxx> wrote: > Hello. > > El 11/10/14 21:19, Theodore Ts'o escribió: >> >> If you are running some workload which is constantly calling fsync(2), >> that will be forcing journal commits, and those turn into cache flush >> commands that force all state to stable storage. Now, if you are >> using CF cards that aren't guaranteed to have power-loss protection >> (hint: even most consumer grade SSD's do not have power loss >> protection --- you have to pay $$$ for enterprise-grade SLC SSD's to >> have power loss protection --- and I'm guessing most CF cards are so >> cheap that they won't make guarantees that all of their flash metadata >> are saved to stable store on a power loss event) the fact that you are >> constantly using fsync(2) may not be providing you with the protection >> you want after a power loss event. >> >> > This got me worried! > How can we test if a device really stores all the data safely after a > barrier and sudden power loss? > Is there a tool for that? > I am thinking something along the lines of a tool that does writes with > some barriers in between and then I unplug the device and run the same tool > but in a "check mode" that tells me if the requested data before the barrier > is really there. > Something sysadmin friendly or maybe even user friendly, but not too > hard to use. > Thanks for your insight! > > -- > Ivan Baldo - ibaldo@xxxxxxxxxxxxx - http://ibaldo.codigolibre.net/ > From Montevideo, Uruguay, at the south of South America. > Freelance programmer and GNU/Linux system administrator, hire me! > Alternatives: ibaldo@xxxxxxxxxxxxxxx - http://go.to/ibaldo > > _______________________________________________ > Ext3-users mailing list > Ext3-users@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/ext3-users -- Sent from the Delta quadrant using Borg technology! _______________________________________________ Ext3-users mailing list Ext3-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/ext3-users
