You are using DDBoost connection to a DataDomain device. Backup to the DataDomain device starts to hang. In the log of Veeam agent that is writing the data to the device you can see agent crash dump is generated after trying to open backup file for read/write access:
In the same log DDboost library logs error Err: 5012:
[TIMESTAMP] < thread_id> DDBoost| ERR |in use. Err: 5012 [TIMESTAMP] < thread_id> DDBoost| >> |Failed to close file '[DFC- datadomain] veeamddboost:/ Job_name/Job_nameTIMESTAMP.vbk ( file_size )' [TIMESTAMP] < thread_id> DDBoost| >> |An exception was thrown from thread [thread_id]
As seen in the generated crash dump, the issue is caused by a crash of libDDBoost.dll library from EMC that Veeam B&R uses to communicate with the device:
*** ERROR: Symbol file could not be found. Defaulted to export symbols for libDDBoost.dll - rax=0000814dfd58178e rbx=00000000017f46b4 rcx=00000000015c48c8 rdx=0000000000000001 rsi=0000000000000000 rdi=0000000000331b36 rip=0000000180093677 rsp=00000000013ac640 rbp=00000000015c48c8 r8=0000000001401380 r9=0000000000000242 r10=0000000060020000 r11=00000000013ac9b0 r12=0000000000000004 r13=000000018017dfb8 r14=0000000000000000 r15=0000000000001000 iopl=0 nv up ei pl nz na pe nc cs=0033 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010202 libDDBoost!ddp_snapshot_list+0x779e7: 00000001`80093677 4d8b4608 mov r8,qword ptr [r14+8] ds:00000000`00000008=????????????????
As advised by EMC, this is related to a bug in DDBoost plugin version 126.96.36.199 or earlier that may cause libDDBoost.dll to crash on ddp_read call.
The issue will be resolved with the release of DDBoost SDK 188.8.131.52 by EMC. The necessary compatible DDOS version for the fix is DDOS 184.108.40.206, and it would also need to be released. The new version of the plugin will be used in Veeam B&R version 9. On earlier versions of Veeam B&R, DDOS, and DDBoost Plugin, connect to DataDomain device over CIFS protocol to work around the issue.
Please apply to this section of product user guide for more information about adding CIFS/SMB (shared folder) -based repository to Veeam B&R.