Re: [weewx-user] weewx.sdb backups revisited

[Greg Troxel]

WindnFog  writes:

> Reading the list archive, the documentation, and searching the Internet 
> about the "best" way to backup SQLite databases, I conclude cold backups 
> are safer than a "hot" cp or rsync. That said, I am doing a hot rsync 
> (takes 2-3 seconds) to another LAN system and a cloud server at 01:18 AM 
> daily. Since I only write archive records to the database at XX:00, XX:05, 
> XX:10, etc., I *think* this is safe. The documentation says:

Not to contradict the advice you've gotten which all seems great, but
you can also do

sqlite3 weewx.sdb .dump > weewxdb.txt

which gets you a text representation that was extracted with database
commands and thus should be ok (fully in a before or after state with
respect to a database transaction) even with concurrent access.  You
would then back up that file.  This scheme is common with the postgresql
world, as I understand it.

-- 
You received this message because you are subscribed to the Google Groups 
"weewx-user" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to weewx-user+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/weewx-user/rmi1ruddoh3.fsf%40s1.lexort.com.

Re: [weewx-user] weewx.sdb backups revisited

[Paul Dunphy]

Thanks,Tom!  I'm not doing anything out of the ordinary, so I shall keep 
doing what I've been doing.


Take care, Paul VE1DX

On 2019-11-12 12:12 p.m., Thomas Keffer wrote:
Unless you are running some unusual service, there should be no 
situations where weewx is modifying the database between archive events.


-tk

On Tue, Nov 12, 2019 at 7:48 AM WindnFog > wrote:


Reading the list archive, the documentation, and searching the
Internet about the "best" way to backup SQLite databases, I
conclude cold backups are safer than a "hot" cp or rsync. That
said, I am doing a hot rsync (takes 2-3 seconds) to another LAN
system and a cloud server at 01:18 AM daily. Since I only write
archive records to the database at XX:00, XX:05, XX:10, etc., I
*think* this is safe. The documentation says:


"Do not make a copy of the SQLite database while in the middle of
a transaction! Schedule the backup for immediately after an
archive record is written, and then make sure the backup completes
before the next archive record arrives. Alternatively, stop WeeWX,
perform the backup, then restart WeeWX."


I prefer not to stop/start weewx every day, but I will if
necessary. Are their situations where some part of weewx could be
modifying the database between the archive writes every 5 minutes?
I have done a couple of restores over the past 4-5 years with no
issues, but am I playing with fire?


What are you guys doing vis-à-vis weewx.sdb backups?


- Paul VE1DX

-- 
You received this message because you are subscribed to the Google

Groups "weewx-user" group.
To unsubscribe from this group and stop receiving emails from it,
send an email to weewx-user+unsubscr...@googlegroups.com
.
To view this discussion on the web visit

https://groups.google.com/d/msgid/weewx-user/dc168739-054a-4b6d-950c-6e9aa7f83e74%40googlegroups.com

.

--
You received this message because you are subscribed to a topic in the 
Google Groups "weewx-user" group.
To unsubscribe from this topic, visit 
https://groups.google.com/d/topic/weewx-user/UWHHpwkoVJ8/unsubscribe.
To unsubscribe from this group and all its topics, send an email to 
weewx-user+unsubscr...@googlegroups.com 
.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/weewx-user/CAPq0zECs61uvq5%3DGKJUbTtcPjyPAKWB0L9LpNgzGZooornCW_A%40mail.gmail.com 
.


--
You received this message because you are subscribed to the Google Groups 
"weewx-user" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to weewx-user+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/weewx-user/fea87b44-d49a-728f-df71-fedefd4c1cbf%40gmail.com.

Re: [weewx-user] weewx.sdb backups revisited

[Thomas Keffer]

Unless you are running some unusual service, there should be no situations
where weewx is modifying the database between archive events.

-tk

On Tue, Nov 12, 2019 at 7:48 AM WindnFog  wrote:

> Reading the list archive, the documentation, and searching the Internet
> about the "best" way to backup SQLite databases, I conclude cold backups
> are safer than a "hot" cp or rsync. That said, I am doing a hot rsync
> (takes 2-3 seconds) to another LAN system and a cloud server at 01:18 AM
> daily. Since I only write archive records to the database at XX:00, XX:05,
> XX:10, etc., I *think* this is safe. The documentation says:
>
>
> "Do not make a copy of the SQLite database while in the middle of a
> transaction! Schedule the backup for immediately after an archive record is
> written, and then make sure the backup completes before the next archive
> record arrives. Alternatively, stop WeeWX, perform the backup, then restart
> WeeWX."
>
>
> I prefer not to stop/start weewx every day, but I will if necessary. Are
> their situations where some part of weewx could be modifying the database
> between the archive writes every 5 minutes? I have done a couple of
> restores over the past 4-5 years with no issues, but am I playing with
> fire?
>
>
> What are you guys doing vis-à-vis weewx.sdb backups?
>
>
> - Paul VE1DX
>
> --
> You received this message because you are subscribed to the Google Groups
> "weewx-user" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to weewx-user+unsubscr...@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/weewx-user/dc168739-054a-4b6d-950c-6e9aa7f83e74%40googlegroups.com
> 
> .
>

-- 
You received this message because you are subscribed to the Google Groups 
"weewx-user" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to weewx-user+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/weewx-user/CAPq0zECs61uvq5%3DGKJUbTtcPjyPAKWB0L9LpNgzGZooornCW_A%40mail.gmail.com.

[weewx-user] weewx.sdb backups revisited

[WindnFog]

Reading the list archive, the documentation, and searching the Internet 
about the "best" way to backup SQLite databases, I conclude cold backups 
are safer than a "hot" cp or rsync. That said, I am doing a hot rsync 
(takes 2-3 seconds) to another LAN system and a cloud server at 01:18 AM 
daily. Since I only write archive records to the database at XX:00, XX:05, 
XX:10, etc., I *think* this is safe. The documentation says:


"Do not make a copy of the SQLite database while in the middle of a 
transaction! Schedule the backup for immediately after an archive record is 
written, and then make sure the backup completes before the next archive 
record arrives. Alternatively, stop WeeWX, perform the backup, then restart 
WeeWX."


I prefer not to stop/start weewx every day, but I will if necessary. Are 
their situations where some part of weewx could be modifying the database 
between the archive writes every 5 minutes? I have done a couple of 
restores over the past 4-5 years with no issues, but am I playing with 
fire? 


What are you guys doing vis-à-vis weewx.sdb backups?


- Paul VE1DX

-- 
You received this message because you are subscribed to the Google Groups 
"weewx-user" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to weewx-user+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/weewx-user/dc168739-054a-4b6d-950c-6e9aa7f83e74%40googlegroups.com.