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Asynchronous Block-Level Storage Replication
461ac8b4cd
Apparently, sysadmins often forget to execute "marsadm up mydata" (or similar) after a failover. Recall the failover command sequence: "marsadm pause-fetch mydata; marsadm primary --force mydata" Some months later, other sysadmins in the group are stumbling over the very old "pause-fetch" after a regular planned handover via "marsadm primary mydata". It works, but the former primary (which is now secondary) does no longer fetch data, because of the very old pause-fetch command which was never reverted. Afterwards, /mars is filling up slowly over a long time. Somewhen later (e.g. a few days), a monitoring alert "/mars too full" is happening at midnight, leading to an unnecessary on-duty call. A different type of monitoring could help, by not only tracking the filling level of /mars, but also view-todo-fetch or similar. However, some people dislike this, because there exist operational use cases (like creation of backups) where pause-fetch is executed _deliberately_ for a longer time. Here is a workaround for a forgotten resume-fetch / up after the first failover: After the _original_ "marsadm primary" or "primary --force" has succeeded by appearance of /dev/mars/mydata, we simply execute the equivalent of "marsadm up mydata". This changes the semantics of the "primary" command. Hopefully no scripts on this world will break. |
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| football@152f499fbd | ||
| kernel | ||
| pre-patches | ||
| scripts | ||
| systemd | ||
| test_suite | ||
| userspace | ||
| .gitattributes | ||
| .gitignore | ||
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| AUTHORS | ||
| ChangeLog | ||
| COPYING | ||
| INSTALL | ||
| NEWS | ||
| README | ||
MARS Long Distance Replication Software See http://schoebel.github.io/mars/ Very detailed documentation / motivation / use cases can be found there. Please look into the docu/ subdirectory. License: GPLv2+ (see file COPYING) Documentation is under FDL. This is intended for the whole project, and is valid for all parts from the original author as well as parts from 1&1. Any further contributors to contrib/ subdirectory are strongly encouraged to put their files also under GPL or FDL, or at least a compatible license (see newest descriptions at fsf.org).