Plug in any USB external drive and this repeats in system.log

Model Name: iMac

Model Identifier: iMac17,1

Processor Name: Intel Core i7

Processor Speed: 4 GHz

Number of Processors: 1

Total Number of Cores: 4

L2 Cache (per Core): 256 KB

L3 Cache: 8 MB

Memory: 32 GB

Boot ROM Version: IM171.0105.B09

SMC Version (system): 2.34f2

Sep 21 08:29:03 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe224e64a80, 3, 0)

Sep 21 08:29:03 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe224d1bbe0, 3, 0)

Sep 21 08:29:03 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe224f28490, 3, 0)

Sep 21 08:29:03 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe224c2aa30, 3, 0)

Sep 21 08:29:03 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe226921af0, 3, 0)

Sep 21 08:29:04 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe22684a310, 3, 0)

Sep 21 08:29:07 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe226a39a70, 3, 0)

Sep 21 08:29:10 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe226a442b0, 3, 0)

Sep 21 08:29:13 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe2268479f0, 3, 0)

Sep 21 08:29:16 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe224e48df0, 3, 0)

Sep 21 08:29:19 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe226828e60, 3, 0)

Sep 21 08:29:22 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe224f2a300, 3, 0)

Sep 21 08:29:25 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe224f287b0, 3, 0)

Sep 21 08:29:28 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe226848ad0, 3, 0)

Sep 21 08:29:31 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe226a53cd0, 3, 0)

Sep 21 08:29:34 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe224d261d0, 3, 0)

Sep 21 08:29:37 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe226843e60, 3, 0)

Sep 21 08:29:40 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe224e4ae10, 3, 0)

Sep 21 08:29:52 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe224f25080, 3, 0)

Sep 21 08:29:52 Parker-6 logd[70]: _volume_contains_cached_data(is /private/var/db/diagnostics/ in /) - YES

Sep 21 08:29:52 Parker-6 logd[70]: 72375512 bytes of purgeable space from log files

Sep 21 08:29:52 Parker-6 logd[70]: _purge_uuidtext only runs at urgency 0 (3)

Sep 21 08:29:52 Parker-6 logd[70]: 0 bytes of purgeable space from uuidtext files

Sep 21 08:29:55 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe226921af0, 3, 0)

Sep 21 08:29:55 Parker-6 logd[70]: _volume_contains_cached_data(is /private/var/db/diagnostics/ in /) - YES

Sep 21 08:29:55 Parker-6 logd[70]: 72375512 bytes of purgeable space from log files

Sep 21 08:29:55 Parker-6 logd[70]: _purge_uuidtext only runs at urgency 0 (3)

Sep 21 08:29:55 Parker-6 logd[70]: 0 bytes of purgeable space from uuidtext files

Sep 21 08:29:58 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe226a4cf30, 3, 0)

Sep 21 08:29:58 Parker-6 logd[70]: _volume_contains_cached_data(is /private/var/db/diagnostics/ in /) - YES

Sep 21 08:29:58 Parker-6 logd[70]: 72375512 bytes of purgeable space from log files

Sep 21 08:29:58 Parker-6 logd[70]: _purge_uuidtext only runs at urgency 0 (3)

Sep 21 08:29:58 Parker-6 logd[70]: 0 bytes of purgeable space from uuidtext files

Sep 21 08:30:01 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe226a53c70, 3, 0)

Sep 21 08:30:01 Parker-6 logd[70]: _volume_contains_cached_data(is /private/var/db/diagnostics/ in /) - YES

Sep 21 08:30:01 Parker-6 logd[70]: 72375512 bytes of purgeable space from log files

Sep 21 08:30:01 Parker-6 logd[70]: _purge_uuidtext only runs at urgency 0 (3)

Sep 21 08:30:01 Parker-6 logd[70]: 0 bytes of purgeable space from uuidtext files

Sep 21 08:30:04 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe226b33af0, 3, 0)

Sep 21 08:30:04 Parker-6 logd[70]: _volume_contains_cached_data(is /private/var/db/diagnostics/ in /) - YES

Sep 21 08:30:04 Parker-6 logd[70]: 72375512 bytes of purgeable space from log files

Sep 21 08:30:04 Parker-6 logd[70]: _purge_uuidtext only runs at urgency 0 (3)

Sep 21 08:30:04 Parker-6 logd[70]: 0 bytes of purgeable space from uuidtext files

Sep 21 08:30:07 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe226a57da0, 3, 0)

Sep 21 08:30:07 Parker-6 logd[70]: _volume_contains_cached_data(is /private/var/db/diagnostics/ in /) - YES

Sep 21 08:30:07 Parker-6 logd[70]: 72375512 bytes of purgeable space from log files

Sep 21 08:30:07 Parker-6 logd[70]: _purge_uuidtext only runs at urgency 0 (3)

Sep 21 08:30:07 Parker-6 logd[70]: 0 bytes of purgeable space from uuidtext files

Sep 21 08:30:10 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe226921d50, 3, 0)

Sep 21 08:30:10 Parker-6 logd[70]: _volume_contains_cached_data(is /private/var/db/diagnostics/ in /) - YES

Sep 21 08:30:10 Parker-6 logd[70]: 72375512 bytes of purgeable space from log files

Sep 21 08:30:10 Parker-6 logd[70]: _purge_uuidtext only runs at urgency 0 (3)

Sep 21 08:30:10 Parker-6 logd[70]: 0 bytes of purgeable space from uuidtext files

Sep 21 08:30:13 Parker-6 logd[70]: _handle_cache_delete_with_urgency(0x7fe22684a310, 3, 0)

Sep 21 08:30:13 Parker-6 logd[70]: _volume_contains_cached_data(is /private/var/db/diagnostics/ in /) - YES

Sep 21 08:30:13 Parker-6 logd[70]: 72375512 bytes of purgeable space from log files

Sep 21 08:30:13 Parker-6 logd[70]: _purge_uuidtext only runs at urgency 0 (3)