I understand database consistency in a transactional database and I'm wondering about the risk of copying weewx.sdb without stopping weewx first. Would you possibly lose an in-flight transaction or might the entire sdb be inconsistent and unusable? An in-flight copy would seem to be similar to losing power to the device vs a graceful shutdown.
On Sunday, January 10, 2021 at 9:46:55 AM UTC-5 peterq...@gmail.com wrote: > I have a script that stops weewx, makes a local copy of the db restarts > weewx and then copies the backup to google drive. > > The copy takes less than 2 minutes so I don't lose data. > > On Sun, Jan 10, 2021, 5:39 AM Tom Keffer <tke...@gmail.com> wrote: > >> Your approach will certainly work, but requires stopping weewxd for what >> could potentially be a long period of time, so you might miss a weather >> event. >> >> Another approach is to use the sqlite3 ".backup" command. Replace your >> tar command with >> >> tar czf $dest/$archive_file $backup_files2 $backup_files3 $backup_files4 >> sqlite3 $backup_files1 ".backup $dest/$backup_files1.backup" >> >> This avoids stopping weewxd, because the sqlite3 utility will take care >> of any necessary locking. However, it has the disadvantage that if sqlite3 >> holds on to the lock for too long, a database write will get delayed and, >> ultimately, could time out, causing weewxd to restart. >> >> Finally, the most sophisticated approach is to incrementally back up the >> database. Take a look at this page on backing up a running database >> <https://sqlite.org/backup.html>. It copies a number of database pages, >> then releases the lock, sleeps for a bit to allow other processes to gain >> access to the database, then goes on to the next set of pages. This allows >> the database to be backed up without stopping weewxd, and without the >> potential hazard of a database timeout. >> >> Something to think about... >> >> -tk >> >> >> >> On Sun, Jan 10, 2021 at 4:01 AM Jan Stelling <stelli...@gmail.com> wrote: >> >>> For some time, I was looking for an easy and independent (from weewx) >>> way to automatically backup my weewx data, as I do not want to lose data if >>> the Micro SD breaks down. >>> Recently, I found this small repo >>> <https://github.com/PapyLeCelte/Weewx-Backup> on github which only >>> contains a backup script file. It mounts a USB drive, stops weewx, creates >>> an archived backup of the most relevant user files and folders on the USB >>> drive, unmounts the drive and restarts weewx. >>> >>> This was almost perfect for me, but I had to introduce some changes to >>> make it suitable for my environment. I forked it >>> <https://github.com/jnstllng/Weewx-Backup> to make it available for >>> others. It now does the following: >>> >>> 1. Stop weewx >>> 2. Create an archived backup on a mounted network drive (under >>> /home/pi/Shares/Temp) >>> 3. Start weewx >>> >>> I tested it manually and running via crontab on my RasPi 3B. >>> >>> Maybe this is useful for some of you... >>> >>> -- >>> 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+...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/weewx-user/2671c065-719a-4435-9657-06841af8fed7n%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/weewx-user/2671c065-719a-4435-9657-06841af8fed7n%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- >> 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+...@googlegroups.com. >> > To view this discussion on the web visit >> https://groups.google.com/d/msgid/weewx-user/CAPq0zEDK%3DkX-zkzewA%2B%2BDXzOkBPMLBUPHaVgJ69qYbaYWNUGzw%40mail.gmail.com >> >> <https://groups.google.com/d/msgid/weewx-user/CAPq0zEDK%3DkX-zkzewA%2B%2BDXzOkBPMLBUPHaVgJ69qYbaYWNUGzw%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> > -- 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/fa03941e-6ea2-41fb-bf62-998ea49651ddn%40googlegroups.com.
