The update or -u option is used by rsync to skip files that are still new in the destination directory.
Does rsync update modified files?īy default, rsync will only copy new or changed files from a source to a destination. So any files that do not exist on the destination will be copied over. This can generally be used when we are performing backups using the link-dest option, while continuing a backup run that got interrupted. Rsync with –ignore-existing-files: We can also skip the already existing files on the destination. Will rsync delete files in destination?.Does rsync overwrite destination files?.What are some of the benefits of using rsync?.Why is rsync not a good backup solution?.Does rsync automatically skip existing files?.What happens if files change during rsync?.What are some disadvantages of using rsync?.If that doesn't seem a likely explanation, I would run a thorough health check on the drive that disconnects, it could be damaged. Their addition should be under the power limit. I would try to get from the vendors document the maximum power requirement for each connected device. Here again, the reset cause the drive to remount under another name The OS waits for a while for the operation to complete, and once the (long-ish) timeout is reached, it resets the data link to the drive in an attempt to restore communication with the device. Defect on an HDD: a write operation (more uncommon read) is carried by the OS, but the HDD fails to confirm commit to medium.README.md for the USB current limit applicable to your model of Raspberry Pi. The reset can have the effect of making the device reappear under another name (sda, sdb.
GRSYNC SKIP EXISTING FULL
Insufficient power delivered over USB: with multiple devices operating at full tilt, the maximum power available over USB ports can be exceeded, and devices reset.I have seen 2 causes for this kind of behaviour: I haven't looked at the log you attached, but the symptom of a drive disappearing and reappearing under a different name tells me the USB link is reset. Personally, I'm going to try an powered USB enclosure for a 3.5" next and see how that works out. There are threads in the forum about this. Some people have tried to use powered USB hubs to workaround this issue, and some of those also ran into an issue with these hubs back-powering the Raspberry Pi, preventing it from rebooting properly. Obviously there's not a lot of power left when you also need to account for the Raspberry Pi 4 itself and the SSD (which likely draws around 2-3W. For that random harddrive, that's 5V*0.8A = 4W during idle. I haven't made any measurements on my own but I read somewhere (and you should take these numbers with a grain of salt) that some random external 2.5" USB harddrive of some TB size drew 1.3 ampere when powering up and then idled at around 0.8 amperes. Most likely the voltage drops below this limit due to the increased current usage, which causes the USB devices to disconnect or misbehave.
A device may draw a maximum of 5 unit loads (500 mA) from a port in USB 2.0 6 (900 mA) in USB 3.0.Īlso according to the USB spec, the USB voltage must be 5V +/- 5% (i.e. The USB 1.x and 2.0 specifications provide a 5 V supply on a single wire to power connected USB devices.Ī unit load is defined as 100 mA in USB 2.0, and 150 mA in USB 3.0.
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