@omatsei I figured out the problem. There appears to be a bug in XO that requires you to check "Check Certificate" and/or "Start TLS", save the configuration, then uncheck them, then save again. Then it should work. The bug is that they're unchecked by default, but apparently they're enabled in the background.

@Danp Yes to both. I've probably restarted the toolstack at least a dozen times, mostly to clear hung tasks. I did notice some weird issues with a secondary SR being disconnected on xcp02, (one of 10 hosts, 9 after I ejected and forgot xcp01), but there's no disks on it. It wasn't being used for anything at all (yet), and it's fine on all the rest. That does lead me to think maybe it was a power bump that rebooted a switch or something though. Maybe it caused some kind of hangup with xcp01 and xcp02, and since xcp01 was the pool master, it cascaded to the other issues I've seen? Could that cause the VM's that were originally running on xcp02 to die and not be able to be recovered easily?

@omatsei I found the following error on the source host, if it helps. I rebooted it and restarted iscsid on both the source and destination hosts, just to make sure nothing was pending or hung. May 28 10:15:32 xcp09 xapi: [error||2507 ||backtrace] SR.scan D:9f4f3c05cc88 failed with exception Storage_error ([S(Redirect);[S(192.168.1.201)]]) May 28 10:15:32 xcp09 xapi: [error||2507 ||backtrace] Raised Storage_error ([S(Redirect);[S(192.168.1.201)]]) May 28 10:15:32 xcp09 xapi: [error||2507 ||backtrace] 1/1 xapi Raised at file (Thread 2507 has no backtrace table. Was with_backtraces called?, line 0 May 28 10:15:32 xcp09 xapi: [error||2507 ||backtrace] May 28 10:15:32 xcp09 xapi: [error||2507 ||storage_interface] Storage_error ([S(Redirect);[S(192.168.1.201)]]) (File "storage/storage_interface.ml", line 436, characters 51-58) May 28 10:15:32 xcp09 xapi: [error||2506 HTTP 127.0.0.1->:::80|Querying services D:6b15aa4c5bcd|storage_interface] Storage_error ([S(Redirect);[S(192.168.1.201)]]) (File "storage/storage_interface.ml", line 431, characters 49-56) May 28 10:15:32 xcp09 xapi: [error||2506 HTTP 127.0.0.1->:::80|Querying services D:6b15aa4c5bcd|storage_interface] Storage_error ([S(Redirect);[S(192.168.1.201)]]) (File "storage/storage_interface.ml", line 436, characters 51-58) Note that 192.168.1.201 is the pool master. I ended up rebooting the pool master after manually migrating VM's off it, and it seems to have fixed the issue. No idea why, but whatever.