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From: Tony Asleson <tasleson@redhat.com>
To: Dave Chinner <david@fromorbit.com>,
	Sweet Tea Dorminy <sweettea@redhat.com>,
	James Bottomley <James.Bottomley@hansenpartnership.com>,
	linux-scsi@vger.kernel.org, linux-block@vger.kernel.org,
	linux-fsdevel@vger.kernel.org
Cc: David Lehman <dlehman@redhat.com>
Subject: Re: [RFC 9/9] __xfs_printk: Add durable name to output
Date: Fri, 10 Jan 2020 10:13:17 -0600	[thread overview]
Message-ID: <2e6a3baa-44af-dac0-5e0c-2bf9a4723e72@redhat.com> (raw)
In-Reply-To: <20200109014117.GB3809@agk-dp.fab.redhat.com>

On 1/8/20 7:41 PM, Alasdair G Kergon wrote:
> The goal of this particular project is to maintain a record of the
> storage configuration as it changes over time.  It should provide a
> quick way to check the state of a system at a specified time in the
> past.

This helps with one aspect of the problem, it leaves a bread crumb which
states that at this point in time /dev/sda was the attachment point for
some device, eg. wwn-0x5002538844580000.

> The initial logging implementation is triggered by storage uevents and
> consists of two components:
> 
> 1. A new udev rule file, 99-zzz-storage-logger.rules, which runs after
> all the other rules have run and invokes:
> 
> 2. A script, udev_storage_logger.sh, that captures relevant
> information about devices that changed and stores it in the system
> journal.
> 
> The effect is to log the data from relevant uevents plus some
> supplementary information (including device-mapper tables, for example).
> It does not yet handle filesystem-related events.
> 
> Two methods to query the data are offered:
> 
> 1. journalctl
> Data is tagged with the identifier UDEVLOG and retrievable as
> key-value pairs.
>   journalctl -t UDEVLOG --output verbose
>   journalctl -t UDEVLOG --output json
>     --since 'YYYY-MM-DD HH:MM:SS' 
>     --until 'YYYY-MM-DD HH:MM:SS'
>   journalctl -t UDEVLOG --output verbose
>     --output-fields=PERSISTENT_STORAGE_ID,MAJOR,MINOR
>      PERSISTENT_STORAGE_ID=dm-name-vg1-lvol0
> 
> 2. lsblkj  [appended j for journal]
> This lsblk wrapper reprocesses the logged uevents to reconstruct a
> dummy system environment that "looks like" the system did at a
> specified earlier time and then runs lsblk against it.

You've outlined how to view and filter on the added data and how to
figure out what the configuration looked like a some point in the past,
that adds one more piece of the puzzle.

However, how would a user simply show all the log messages for a
specific device over time?  It looks like journalctl would need to have
logic added to make this a seamless user experience, yes?

Perhaps I'm missing something that makes the outlined use case above work?


  parent reply	other threads:[~2020-01-10 16:13 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-23 22:55 [RFC 0/9] Add persistent durable identifier to storage log messages Tony Asleson
2019-12-23 22:55 ` [RFC 1/9] lib/string: Add function to trim duplicate WS Tony Asleson
2019-12-23 23:28   ` Matthew Wilcox
2020-01-02 22:52     ` Tony Asleson
2020-01-03 14:30       ` Tony Asleson
2019-12-23 22:55 ` [RFC 2/9] printk: Bring back printk_emit Tony Asleson
2019-12-23 22:55 ` [RFC 3/9] printk: Add printk_emit_ratelimited macro Tony Asleson
2019-12-23 22:55 ` [RFC 4/9] struct device_type: Add function callback durable_name Tony Asleson
2019-12-23 22:55 ` [RFC 5/9] block: Add support functions for persistent durable name Tony Asleson
2019-12-23 22:55 ` [RFC 6/9] create_syslog_header: Add " Tony Asleson
2019-12-24  0:54   ` James Bottomley
2020-01-02 22:53     ` Tony Asleson
2019-12-23 22:55 ` [RFC 7/9] print_req_error: Add persistent " Tony Asleson
2019-12-23 22:55 ` [RFC 8/9] ata_dev_printk: Add durable name to output Tony Asleson
2019-12-24  0:56   ` James Bottomley
2019-12-23 22:55 ` [RFC 9/9] __xfs_printk: " Tony Asleson
2020-01-04  2:56   ` Dave Chinner
2020-01-06  2:45     ` Tony Asleson
2020-01-06 22:02       ` Dave Chinner
2020-01-07  0:19         ` Sweet Tea Dorminy
2020-01-07  1:23           ` Dave Chinner
2020-01-07 17:01             ` Tony Asleson
2020-01-08  2:10               ` Dave Chinner
2020-01-08 16:53                 ` Tony Asleson
2020-01-09  1:41                   ` Alasdair G Kergon
2020-01-09 23:22                     ` Dave Chinner
2020-01-10  1:28                       ` Alasdair G Kergon
2020-01-10 16:13                     ` Tony Asleson [this message]
2019-12-24  0:50 ` [RFC 0/9] Add persistent durable identifier to storage log messages James Bottomley
2020-01-02 22:52   ` Tony Asleson

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