diff options
| -rw-r--r-- | docs/system/deprecated.rst | 18 | ||||
| -rw-r--r-- | util/mmap-alloc.c | 2 |
2 files changed, 20 insertions, 0 deletions
diff --git a/docs/system/deprecated.rst b/docs/system/deprecated.rst index 70e08baff6..94fb7dbf4e 100644 --- a/docs/system/deprecated.rst +++ b/docs/system/deprecated.rst @@ -221,6 +221,24 @@ This machine is deprecated because we have enough AST2500 based OpenPOWER machines. It can be easily replaced by the ``witherspoon-bmc`` or the ``romulus-bmc`` machines. +Backend options +--------------- + +Using non-persistent backing file with pmem=on (since 6.1) +'''''''''''''''''''''''''''''''''''''''''''''''''''''''''' + +This option is used when ``memory-backend-file`` is consumed by emulated NVDIMM +device. However enabling ``memory-backend-file.pmem`` option, when backing file +is (a) not DAX capable or (b) not on a filesystem that support direct mapping +of persistent memory, is not safe and may lead to data loss or corruption in case +of host crash. +Options are: + + - modify VM configuration to set ``pmem=off`` to continue using fake NVDIMM + (without persistence guaranties) with backing file on non DAX storage + - move backing file to NVDIMM storage and keep ``pmem=on`` + (to have NVDIMM with persistence guaranties). + Device options -------------- diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c index 838e286ce5..893d864354 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -225,6 +225,8 @@ static void *mmap_activate(void *ptr, size_t size, int fd, "crash.\n", file_name); g_free(proc_link); g_free(file_name); + warn_report("Using non DAX backing file with 'pmem=on' option" + " is deprecated"); } /* * If mmap failed with MAP_SHARED_VALIDATE | MAP_SYNC, we will try |