Hi, I easily overcame the libata changeover (/dev/sda) with my IDE drives. I never (have a need to) hot swap any drives. And always power down my system when not in use, and disconnect the mains power board. (Surge protectors have their limitations.) Haven't used SATA drives until the last couple days. Haven't had two drives in at same time yet. Just fired it up and noticed that the SATA dual drive caddy from Lindy has a LED for each disk, but that it doesn't light up when read/writing. Hmm. Will have to talk with them about that. When doing backups, it will always be from a cold start with both HDDs already inserted. Will think a bit more about verifying identity of source and destination drives, in this SATA world. Carl p.s. Still no advice from anyone about the original UUID editing-out that I posted. We're too busy with the meta-picture. On 22/04/14 16:23, Russell Coker wrote:
On Tue, 22 Apr 2014 14:03:30 Carl Turney wrote:
In my backing up system, I'm clear about the physical location of master and backup drives, and include a visual (LED-on) confirmation of drive assignment before the shell script starts the RSYNC command.
First time using SATA. Hope it doesn't introduce any randomising factors.
With IDE there were usually two cables in a system which were often labeled as "primary" and "secondary" (or similar). Each cable had at most two connections and the devices attached could be jumpered for master/slave or "CS" to determine things by cable position. The scope for getting things wrong was limited, particularly on systems which wouldn't boot from the secondary cable and when drive names were /dev/hda and /dev/hdc based on cabling.
When the kernel went to libata for IDE and the drives were named /dev/sda, /dev/sdb, etc sequentially things got a little more complicated. Unplugging the drive which used to be /dev/sdb would rename the device that used to be /dev/sdc and potentially cause problems.
With SATA it's even more difficult due to the unclear labeling of motherboards. A motherboard that has 4+ SATA ports with no clear labels showing which is which is fairly common. Mapping between physical ports and /dev/sda etc also isn't clear to me. It could be that the mapping is expected to be constant but my observation doesn't bear that out (maybe I dealt with some motherboards that did the wrong thing - if so such motherboards are common). Then there's the issue of USB CF/SD card readers getting assigned /dev/sdX and making the device for your backup vary depending on whether you plugged your backup device in before turning your monitor on (which happens to me).
UUIDs are annoying when you want to do a backup/format/restore on the root filesystem without modifying the boot loader configuration. But apart from that they work well.