SCSI Drivers Loading Order
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- The mid-layer driver must be loaded before the others.
- When an HBA driver is loaded, it causes the mid-layer to perform
a SCSI scan, in order to find any LUNs accessible to it, and attach
upper-layer devices to them.
- This means that the order of HBA drivers loading is crucial to device
naming: if we have HBA 1 that sees disk A, and HBA 2 that sees disk B,
loading the the driver for HBA 1 first, will mean that disk A will be
seen via /dev/sda, while disk B will be seen via /dev/sdb.
- In a SAN this is even more problematic - the order of discovery of
different RAIDs will change the target ID (and device file attaching)
for them. Anyone said "data corruption"?