Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Dear friends One kind clarification the manual of 8.4 says about disk-barriers "disk-barrier Use disk barriers to make sure that requests are written to disk in the right order. Barriers ensure that all requests submitted before a barrier make it to the disk before any requests submitted after the barrier. This is implemented using 'tagged command queuing' on SCSI devices and 'native command queuing' on SATA devices." and at the end of the disk -barrier it says "Only some devices and device stacks support this method. The device mapper (LVM) only supports barriers in some configurations." this last sentence confuses me a bit, since in XenServer it is used LVM and I'm using it and at the very end of the section it says "Depending on the I/O stack, write requests can be reordered, and they can be submitted in a different order on different cluster nodes. This can result in data loss or corruption. Therefore, turning off all three methods of controlling write ordering is strongly discouraged. " Ok. So what? What it is best to do with a XenServer environment with LVM on SATA disks? Thank you for hinting Robert