open-cas-linux/utils/opencas.conf.5
Jan Musial aaedfb35dd Change startup procedure
Current startup procedure works on an assumption that we will
deal with asynchronously appearing devices in asynchronous way
(udev rules) and synchronous events in the system (systemd units)
won't interfere. If we would break anything (mounts) we would just
take those units and restart them. This tactic was working as long
as resetting systemd units took reasonable time.

As hackish as it sounds it worked in all systems that the software
has been validated on. Unfortunately it stopped working because
of *.mount units taking MUCH longer time to restart even on
mainstream OSes, so it's time to change.

This change implements open-cas systemd service which will wait
synchronously with systemd bootup process for all required Open CAS
devices to start. If they don't we fail the boot process just as
failing mounts would. We also make sure that this process takes place
before any mounts (aside from root FS and other critical FS's) are
even attempted. Now opencas-mount-utility can be discarded.

To override this behaviour on per-core basis you can specify
lazy_startup=true option in opencas.conf.

Signed-off-by: Jan Musial <jan.musial@intel.com>
2019-11-14 12:20:08 +01:00

63 lines
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.TH opencas.conf 5 __CAS_DATE__ v_CAS_VERSION__
.SH NAME
opencas.conf \- cas configuration file.
.SH SYNOPSIS
.B /etc/opencas/opencas.conf
.SH COPYRIGHT
Copyright(c) 2012-2019 by the Intel Corporation.
.SH DESCRIPTION
Contains configurations for cache and core devices to run cache on system startup. Constist of following sections:
.RS 3
.TP
\fBversion\fR First line has to be version tag.
.TP
\fB[caches]\fR Caches configuration. Following columns are required:
.RS 5
.IP
Cache ID <1-16384>
.br
Cache device <DEVICE>
.br
Cache mode {wt|wb|wa|pt|wo}
.br
Extra fields (optional) ioclass_file=<file>,cleaning_policy=<alru,nop>,promotion_policy=<always,nhit>
.RE
.TP
\fB[cores]\fR Cores configuration. Following columns are required:
.RS 5
.IP
Cache ID <1-16384>
.br
Core ID <0-4095>
.br
Core device <DEVICE>
.br
Extra fields (optional) lazy_startup=<true,false>
.RE
.TP
\fBNOTES\fR
.RS
1) It is highly recommended to specify cache/core device using path that is constant across reboots - e.g. disk device links in /dev/disk/by-id/, preferably those using device WWN if available: /dev/disk/by-id/wwn-0x123456789abcdef0. Referencing devices via /dev/sd* may result in cache misconfiguration after system reboot due to change(s) in drive order.
.TP
2) To specify use of the IC Classification file, place ioclass_file=path/to/file.csv in caches configuration section under Extra fields (optional)
.SH FILES
.TP
/etc/opencas/opencas.conf
Contains configurations for cache and core devices to run cache on system startup or via cas tool.
.SH REPORTING BUGS
Patches and issues may be submitted to the official repository at
\fBhttps://open-cas.github.io\fR
.SH SEE ALSO
.TP
casctl(8), casadm(8)