On 3/9/2019 5:05 AM, Ciprian Dorin Craciun wrote: > [I'm adding to the previous question also the issue of salvaging. I'm > quoting what I've asked on a previous thread.] > > BTW, on the topic of volume salvaging, when I define my DAFS / FS node > I start a node of `salvager` (for FS) and `dasalvager` and > `salvageserver`. However looking at the running processes the > `salvager` and `dasalvager` don't seem to be running after the initial > startup. Thus I wonder how the salvage process actually happens? > > Does the `fileserver` / `dafileserver` actually start the salvage > process, or do they communicate this to the `bos` to restart only that > service?
The BOS Overseer Service plays a number of roles:
1. It is a cross-platform remote management interface for the
creating, deleting, starting, and stopping b-node services
There are four types of bnodes:
a. simple - any single process service for example ptserver,
vlserver, buserver, one of the MIT/Heimdal kerberos services,
etc. Simple services do not have any special interaction
with bosserver.
b. cron - like a simple bnode but which can be executed once
at start (now), daily, or weekly
c. fs - a bnode which defines the process group for
the legacy fileserver. The bosserver has special knowledge
related to process restart in case of failure and integration
with the "bos salvage" command.
d. dafs - a bnode which defines the process group for the
demand attach fileserver. The bosserver has special knowledge
related to process restart in case of failure and integration
with the "bos salvage" command.
2. The bosserver is responsible for managing the content of many
configuration files including BosConfig, UserList, and
the server version of the CellServDB file. The KeyFile can
also be updated via bosserver. The files other than BosConfig
are shared with the AFS services
3. The bosserver is used to request manual salvages of individual
volumes or whole partitions. When the "fs" bnode is in use,
the bnode will be stopped and started while the salvage takes
place. With the "dafs" bnode, single volume salvages do not
require the "dafs" bnode to be halted but full partition
salvages do.
4. Remote fetching of log files.
5. Remote execution of arbitrary commands.
Most but not all of these functions could be performed with other tools.
Managing the special inter-dependencies of the "fs" and "dafs" bnode
processes and salvaging are the two exceptions.
Jeffrey Altman
<<attachment: jaltman.vcf>>
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