illumos gate

I have several servers working on oi_151a.
They are cifs servers in AD mode.
Have 2 domain controllers always online.
Some times my users can't connect to server.
In /var/adm/messages i see this:

Nov 11 13:05:25 sun smbd[645]: [ID 807464 daemon.error] ndr_rpc_bind: smbrdr_ctx_new(S=dc1, D=PIASTRO, U=SUN$), err=2
Nov 11 13:05:25 sun smbd[645]: [ID 807464 daemon.error] ndr_rpc_bind: smbrdr_ctx_new(S=dc1, D=PIASTRO, U=SUN$), err=134
Nov 11 13:05:26 sun smbd[645]: [ID 807464 daemon.error] ndr_rpc_bind: smbrdr_ctx_new(S=dc1, D=PIASTRO, U=SUN$), err=17
Nov 11 13:05:26 sun last message repeated 2 times
Nov 11 13:25:24 sun smbd[645]: [ID 807464 daemon.error] ndr_rpc_bind: smbrdr_ctx_new(S=dc1, D=PIASTRO, U=SUN$), err=17
Nov 11 13:25:24 sun last message repeated 3 times
Nov 11 15:29:58 sun smbd[645]: [ID 801593 daemon.error] idmap_get_mappings: RPC error
Nov 11 15:29:58 sun smbd[645]: [ID 807464 daemon.error] ndr_rpc_bind: smbrdr_ctx_new(S=dc1, D=PIASTRO, U=SUN$), err=4
Nov 11 15:29:58 sun smbd[645]: [ID 801593 daemon.error] idmap_get_mappings: RPC error
Nov 11 15:29:58 sun smbd[645]: [ID 807464 daemon.error] ndr_rpc_bind: smbrdr_ctx_new(S=dc1, D=PIASTRO, U=SUN$), err=4
Nov 11 15:29:58 sun last message repeated 2 times
Nov 11 15:29:58 sun smbd[645]: [ID 801593 daemon.error] idmap_get_mappings: RPC error
Nov 11 15:29:58 sun last message repeated 7 times
Nov 11 15:29:59 sun genunix: [ID 138131 kern.notice] NOTICE: smb_smb_treeconnect: (\\dc1\IPC$) failed, status=0x0
Nov 11 15:29:59 sun smbd[645]: [ID 807464 daemon.error] ndr_rpc_bind: smbrdr_ctx_new(S=dc1, D=PIASTRO, U=SUN$), err=134
Nov 11 15:29:59 sun genunix: [ID 138131 kern.notice] NOTICE: smb_smb_treeconnect: (\\dc1\IPC$) failed, status=0x0
Nov 11 15:29:59 sun smbd[645]: [ID 807464 daemon.error] ndr_rpc_bind: smbrdr_ctx_new(S=dc1, D=PIASTRO, U=SUN$), err=134
Nov 11 15:30:29 sun idmapd[23436]: [ID 280452 daemon.error] Error:  smb_lookup_sid failed.
Nov 11 15:30:29 sun idmapd[23436]: [ID 455671 daemon.error] Check SMB service (svc:/network/smb/server).
Nov 11 15:30:29 sun idmapd[23436]: [ID 174421 daemon.error] Check connectivity to Active Directory.
Nov 11 15:30:29 sun idmapd[23436]: [ID 280452 daemon.error] Error:  smb_lookup_sid failed.
Nov 11 15:30:29 sun idmapd[23436]: [ID 455671 daemon.error] Check SMB service (svc:/network/smb/server).
Nov 11 15:30:29 sun idmapd[23436]: [ID 174421 daemon.error] Check connectivity to Active Directory.
Nov 11 15:30:29 sun idmapd[23436]: [ID 280452 daemon.error] Error:  smb_lookup_sid failed.
Nov 11 15:30:29 sun idmapd[23436]: [ID 455671 daemon.error] Check SMB service (svc:/network/smb/server).
Nov 11 15:30:29 sun idmapd[23436]: [ID 174421 daemon.error] Check connectivity to Active Directory.
Nov 11 15:30:29 sun idmapd[23436]: [ID 280452 daemon.error] Error:  smb_lookup_sid failed.
Nov 11 15:30:29 sun idmapd[23436]: [ID 455671 daemon.error] Check SMB service (svc:/network/smb/server).
Nov 11 15:30:29 sun idmapd[23436]: [ID 174421 daemon.error] Check connectivity to Active Directory.
Nov 11 15:30:29 sun idmapd[23436]: [ID 280452 daemon.error] Error:  smb_lookup_sid failed.

[cut]

Nov 11 15:30:30 sun idmapd[23436]: [ID 455671 daemon.error] Check SMB service (svc:/network/smb/server).
Nov 11 15:30:30 sun idmapd[23436]: [ID 174421 daemon.error] Check connectivity to Active Directory.
Nov 11 15:30:54 sun smbd[645]: [ID 588498 daemon.notice] smbd_door_fini[doorsrv]: 13 remaining
Nov 11 15:31:08 sun smbd[645]: [ID 702911 daemon.notice] smbd_dc_monitor: domain service not responding
Nov 11 15:31:08 sun smbd[645]: [ID 702911 daemon.notice] smbd_dc_update: piastro.local: locate failed
Nov 11 15:31:12 sun svc.startd[10]: [ID 122153 daemon.warning] svc:/network/smb/server:default: Method or service exit timed out.  Killing contract 98.
Nov 11 15:31:12 sun svc.startd[10]: [ID 748625 daemon.error] network/smb/server:default failed: transitioned to maintenance (see 'svcs -xv' for details)
Nov 11 15:31:12 sun fmd: [ID 377184 daemon.error] SUNW-MSG-ID: SMF-8000-YX, TYPE: defect, VER: 1, SEVERITY: major
Nov 11 15:31:12 sun EVENT-TIME: Fri Nov 11 15:31:12 MSK 2011
Nov 11 15:31:12 sun PLATFORM: A785GM-M5, CSN: -, HOSTNAME: sun
Nov 11 15:31:12 sun SOURCE: software-diagnosis, REV: 0.1
Nov 11 15:31:12 sun EVENT-ID: 5080b17c-0a02-eaf1-a30c-aa5b14acc4e5
Nov 11 15:31:12 sun DESC: A service failed - a start, stop or refresh method failed.
Nov 11 15:31:12 sun   Refer to http://sun.com/msg/SMF-8000-YX for more information.
Nov 11 15:31:12 sun AUTO-RESPONSE: The service has been placed into the maintenance state.
Nov 11 15:31:12 sun IMPACT: svc:/network/smb/server:default is unavailable.
Nov 11 15:31:12 sun REC-ACTION: Run 'svcs -xv svc:/network/smb/server:default' to determine the generic reason why the service failed, the location of any logfiles, and a list of other services impacted.
Nov 11 15:31:13 sun idmapd[23436]: [ID 280452 daemon.error] Error:  smb_lookup_sid failed.
Nov 11 15:31:13 sun idmapd[23436]: [ID 455671 daemon.error] Check SMB service (svc:/network/smb/server).
Nov 11 15:31:13 sun idmapd[23436]: [ID 174421 daemon.error] Check connectivity to Active Directory.
Nov 11 15:31:13 sun idmapd[23436]: [ID 280452 daemon.error] Error:  smb_lookup_sid failed.

Restart of smb/server and idmap services helps sometimes. And sometimes only reboot helps me.
Any one seen such bug?
How can i fix it?