Many thanks to all who responded, most particularly to Richard Sims, who (no surprise) steered me in the right direction.
In brief, on a whim, I restarted the TSM server (potentially costly whim); this didn't help, but it did change the error tsm: ADSM2>def logcopy /dev/rD100b2L01L002 /dev/rD100b2L01L002 ANR2442E DEFINE LOGCOPY: Volume /dev/rD100b2L01L002 is not a defined recovery log volume. ANS8001I Return code 11. tsm: ADSM2>def logvol /dev/rD100b2L01L002 ANR2452E DEFINE LOGVOLUME: Maximum recovery log capacity exceeded. ANS8001I Return code 14. tsm: ADSM2>vary on /dev/rD100b2L01L002 ANR2422E VARY ONLINE: Volume /dev/rD100b2L01L002 is not a defined disk volume. ANS8001I Return code 11. The only documentation for ANR2442E I could find on-line was for the DELETE LOGVOLUME command - no help there. Richard, however, had mentioned the /tmp/adsm.disk.dev.<raw name> file So I looked: $ ls -ltr adsm* -rw-r--r-- 1 adsm2 adsm2 19 Jun 28 13:48 adsm.disk.dev.rD100b2L01L001 -rw-r--r-- 1 adsm2 adsm2 19 Jun 29 13:32 adsm.disk.dev.rD200b2L01L002 -rw-r--r-- 1 adsm2 adsm2 19 Jun 29 13:32 adsm.disk.dev.rD200b2L01L001 -rw-r--r-- 1 adsm2 adsm2 19 Jun 29 13:32 adsm.disk.dev.rD101b2D01D004 -rw-r--r-- 1 adsm2 adsm2 19 Jun 29 13:32 adsm.disk.dev.rD101b2D01D003 -rw-r--r-- 1 adsm2 adsm2 19 Jun 29 13:32 adsm.disk.dev.rD101b2D01D002 -rw-r--r-- 1 adsm2 adsm2 19 Jun 29 13:32 adsm.disk.dev.rD101b2D01D001 -rw-r--r-- 1 adsm2 adsm2 19 Jun 29 13:32 adsm.disk.dev.rD111b2D01D006 -rw-r--r-- 1 adsm2 adsm2 19 Jun 29 13:32 adsm.disk.dev.rD111b2D01D005 -rw-r--r-- 1 adsm2 adsm2 19 Jun 29 13:32 adsm.disk.dev.rD111b2D01D004 -rw-r--r-- 1 adsm2 adsm2 19 Jun 29 13:32 adsm.disk.dev.rD111b2D01D003 -rw-r--r-- 1 adsm2 adsm2 19 Jun 29 13:32 adsm.disk.dev.rD111b2D01D002 -rw-r--r-- 1 adsm2 adsm2 19 Jun 29 13:32 adsm.disk.dev.rD111b2D01D001 -rw-r--r-- 1 adsm2 adsm2 19 Jun 29 13:32 adsm.disk.dev.rD101b2D01D006 -rw-r--r-- 1 adsm2 adsm2 19 Jun 29 13:32 adsm.disk.dev.rD101b2D01D005 The later timestamps corresponded to the recent restart. Noting that there wasn't one for rD100b2L01L002, I decided to try again - and this time... tsm: ADSM2>def logcopy /dev/rD200b2L01L002 /dev/rD100b2L01L002 ANR2262I Recovery log volume copy /dev/rD100b2L01L002 defined; synchronization process started (process ID 3). ANS8003I Process number 3 started. Huh? So I renamed the adsm.disk.dev.rD100b2L01L001 file, and tsm: ADSM2>def logcopy /dev/rD200b2L01L001 /dev/rD100b2L01L001 ANR2262I Recovery log volume copy /dev/rD100b2L01L001 defined; synchronization process started (process ID 4). ANS8003I Process number 4 started. And now the world is as it should be: tsm: ADSM2>q logvol Volume Name Copy Volume Name Copy Volume Name Copy (Copy 1) Status (Copy 2) Status (Copy 3) Status ---------------- ------ ---------------- ------ ---------------- ------ /dev/rD100b2L01- Sync'd /dev/rD200b2L01- Sync'd Undef- L002 L002 ined /dev/rD100b2L01- Sync'd /dev/rD200b2L01- Sync'd Undef- L001 L001 ined On to the next issue..