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Automatic backups don't happen reliably with client on UPS RRS feed

  • Question

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    I know this issue has been discussed quite a bit in other posts, but I'd like to add my 2 cents.

    After a lot of trial and error of different configurations, I would like to suggest that this IS either a Windows issue or WHS Connector issue, rather than a UPS issue.

    I have Win XP Pro SP3 with an APC UPS using the built in Windows UPS driver (which is actually from APC, BTW).

    Manual backups and automatic backups that are initiated when the system is awake complete just fine. This implies that the system (Windows and WHS Connector) DOES NOT think the system is running on battery.

    When the UPS USB cable is plugged in, automatic backups that are initiated with the system waking from S3 sleep DO NOT happen reliably. The system wakes up during the backup time window; usually, but not always, never even tries to initiate a backup; and then goes back to sleep. It would be nice if the WHS logs reported that a backup will not be attempted due to the system being on battery power.

    When the UPS USB cable is unplugged, automatic backups that are initiated with the system waking from S3 sleep DO happen reliably.

    I have made the observation that, when the UPS USB cable is plugged in, the amount of time for the system to detect and report that it is running on AC power rather than on battery power after waking from S3 sleep is quite variable (simply from observing the taskbar icon change from battery mode to AC power mode). I would suggest that the backup problem is probably related to either Windows reporting or WHS Connector requesting the power status too soon after waking from sleep. This could certainly explain the variable nature of automatic backups when using a UPS.

    Does anyone know if the problem has been analyzed from this point of view?

    Sunday, December 7, 2008 4:21 PM

Answers

  • Yes, I'm pretty sure Microsoft has looked at this problem. Their recommendation is to not use a UPS with a desktop PC, which I don't think is entirely realistic. However, I'm not sure it's a problem that can actually be solved, at least not in the general sense, by Microsoft alone. There are hardware and software factors at play, and Microsoft has partial control (at best) over only the software side of the equation.

    I'm not on the WHS team, I just post a lot. :)
    Sunday, December 7, 2008 4:46 PM
    Moderator

All replies

  • Hi John,
    this is a known issue. A connected UPS seems to make the software think, that the system is running on battery, and systems running on battery are not backed up automatically.
    Best greetings from Germany
    Olaf
    Sunday, December 7, 2008 4:27 PM
    Moderator
  • Yes, I'm pretty sure Microsoft has looked at this problem. Their recommendation is to not use a UPS with a desktop PC, which I don't think is entirely realistic. However, I'm not sure it's a problem that can actually be solved, at least not in the general sense, by Microsoft alone. There are hardware and software factors at play, and Microsoft has partial control (at best) over only the software side of the equation.

    I'm not on the WHS team, I just post a lot. :)
    Sunday, December 7, 2008 4:46 PM
    Moderator
  • Thanks for the replies, but what does not seem to be answered then, is why the backups would succeed just fine when initiated manually or automatic backups when the system is awake when the automatic backup is initiated. I don't see why this is anything other than a software issue - either Windows or WHS Connector (i.e. the code doesn't wait long enough after wake up), since the backups NEVER fail in the conditions in my first sentence.

    Sunday, December 7, 2008 4:56 PM
  • A manual backup will always run, at least until the computer shuts down due to lack of battery power. As for automatic backups, the computer has determined that it's not on battery i it's been powered up for some time.

    I think you're right that the connector fails to "wait long enough". However, "long enough" may be an unreasonable length of time. On battery, many computers disable certain components to extend battery life, including (usually) network adapters. The time required to re-enable the adapter, reestablish a connection to the network (i.e. obtain an IP address and determine that the network itself is functioning), and then establish a connection to the server may be several minutes.

    I'm not on the WHS team, I just post a lot. :)
    Sunday, December 7, 2008 5:20 PM
    Moderator
  • Yes, and many of the steps you mention above need to occur after wake up regardless of whether on battery or AC. So perhaps its not merely an issue of waiting long enough for the system to report that its now on AC, but the timing of many of these steps in relation to each other. I won't pretend to know how these steps are sequenced when a client wakes up to initiate a backup, but it wouldn't seem that difficult for Microsoft to make sure they're doing them in the correct order and waiting long enough at any steps that depend on hardware (i.e. UPS) reporting a state change to the software.
    Sunday, December 7, 2008 5:30 PM