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Hi Robb, Does this occur on a machine where you are creating images from live databases? Since SQL Clone uses the Volume Shadow Copy Service to do this, there can be conflicts with other software which is trying to use the same service at the same time (we've heard of Veeam preventing SQL Clone from creating images because of this). If you're creating images from backup, this service isn't used. It would also be interesting to hear the error message that you're getting from Veeam to see whether it's likely to be this issue or something else. Chris / comments
Hi Robb,Does this occur on a machine where you are creating images from live databases? Since SQL Clone uses the Volume Shadow Copy Service to do this, there can be conflicts with other software wh...
Usually the reason that this would occur would be because the Clone Agent believes that it can no longer access the image (at which point the clones would become invalid to access, so we attempt to kill connections and detach the clone database until the image is availabl). Given that you say that the image is on the same machine, it sounds like this is something worth investigating, since the image shouldn't be intermittently unavailable. Could you share your agent logs with us as described in https://documentation.red-gate.com/clone2/troubleshooting/log-locations? It may be preferable to open a ticket by emailing support@red-gate.com rather than posting them on the forums. / comments
Usually the reason that this would occur would be because the Clone Agent believes that it can no longer access the image (at which point the clones would become invalid to access, so we attempt to...
Usually the reason that this would occur would be because the Clone Agent believes that it can no longer access the image (at which point accessing clone databases causes file system errors, so we attempt to kill connections and detach the clone database until the image is available again). Given that you say that the image is on the same machine, it sounds like this is something worth investigating, since the image shouldn't be intermittently unavailable. Could you share your agent logs with us as described in https://documentation.red-gate.com/clone2/troubleshooting/log-locations? It may be preferable to open a ticket by emailing support@red-gate.com rather than posting them on the forums. / comments
Usually the reason that this would occur would be because the Clone Agent believes that it can no longer access the image (at which point accessing clone databases causes file system errors, so we ...
Usually the reason that this would occur would be because the Clone Agent believes that it can no longer access the image (at which point accessing clone databases causes file system errors, so we attempt to kill connections and detach the clone database until the image is available again). Given that you say that the image is on the same machine, it sounds like this is something worth investigating, since the image shouldn't be intermittently unavailable. Could you share your agent logs with us as described in https://documentation.red-gate.com/clone2/troubleshooting/log-locations? It may be preferable to open a ticket by emailing support@red-gate.com rather than posting them on the forums. / comments
Usually the reason that this would occur would be because the Clone Agent believes that it can no longer access the image (at which point accessing clone databases causes file system errors, so we ...
The only strict hardware requirement is a 64-bit (x86-64) CPU, as this is required for the Windows Virtual Disk Service. We would recommend hosting images on a fileshare on a high-performance, reliable SAN on the same LAN as machines which will have clones. This is because clone data files only store changes made to that clone database, and all unmodified data must be read from the image file. A reliable connection is therefore important to ensure that SQL Server is able to access data whenever it is required, and a low-latency, high-bandwidth connection to images stored on hardware potentially capable of handling concurrent requests from multiple clones will improve performance. / comments
The only strict hardware requirement is a 64-bit (x86-64) CPU, as this is required for the Windows Virtual Disk Service.We would recommend hosting images on a fileshare on a high-performance, relia...
The error message "The device is not ready" (error 21) usually means that the network connection between the machine with the clone and the location where the image is stored is interrupted. In many cases, this can be difficult to recover without restarting SQL Server, since it puts the database into an error state, but that doesn't seem to be the situation here. Do you know of any steps that could be used to reproduce the problem? We might also be able to learn something from a full agent log file, if you wanted to share that with us through a support ticket. / comments
The error message "The device is not ready" (error 21) usually means that the network connection between the machine with the clone and the location where the image is stored is interrupted. In man...
You can find information about locating the log files here: https://documentation.red-gate.com/clone2/troubleshooting/log-locations It's the last part (SQL Clone Agent Service) which is most likely to be helpful. If you could open a ticket with support@red-gate.com and send the logs along then we can see if there's anything we can determine from them, thanks! / comments
You can find information about locating the log files here:https://documentation.red-gate.com/clone2/troubleshooting/log-locationsIt's the last part (SQL Clone Agent Service) which is most likely t...
Communication between the clone VHD and its parent image VHD is handled by the VHD driver and SMB over the underlying network, but the clone database appears to SQL Server as though it is on standard local disk. If the VHD driver isn't able to contact the image VHD to access data from it, it often responds with error 21 (the device is not ready). SQL Server responds to this error when accessing the disk by blocking access to the database, which can only be reliably resolved by restarting SQL Server. SQL Clone tries to reduce the risk of this happening by detaching the database when Windows informs the agent that the image is unreachable, so that it can reattach it once the connection is restored. However, Windows doesn't inform of this instantly, and if SQL Server tries to access the database first, you can get into the situation that you describe. To prevent this from happening, there needs to be a reliable connection between the image and clone. Using a SAN for images and co-locating images with machines that will receive clones on the same LAN is recommended. / comments
Communication between the clone VHD and its parent image VHD is handled by the VHD driver and SMB over the underlying network, but the clone database appears to SQL Server as though it is on standa...
If the instance has recently been configured, then restarting SQL Clone Agent might be required to pick it up. Otherwise, when you are adding the instance manually, are you including the machine name when specifying the instance? The "SQL Server Instance Name" box should just contain the name of the instance, not the server as well. If you need to specify a port as well, you should be able to specify it as e.g.: INSTANCENAME,1234 / comments
If the instance has recently been configured, then restarting SQL Clone Agent might be required to pick it up.Otherwise, when you are adding the instance manually, are you including the machine nam...
You need to have SQL Clone Agent installed on each machine where you want to create image and/or clones (since it needs to work with virtual disks and potentially the Shadow Copy service). Is the staging instance on a different machine to the dev server? Installing a copy of the Agent there should allow Clone to work with that instance if so. / comments
You need to have SQL Clone Agent installed on each machine where you want to create image and/or clones (since it needs to work with virtual disks and potentially the Shadow Copy service). Is the s...