NAME¶

lsm_volume_cache_info - Query RAM cache information for the specified volume.

SYNOPSIS¶

int lsm_volume_cache_info (lsm_connect *conn, lsm_volume *volume, uint32_t *write_cache_policy, uint32_t *write_cache_status, uint32_t *read_cache_policy, uint32_t *read_cache_status, uint32_t *physical_disk_cache, lsm_flag flags);

ARGUMENTS¶

conn

Valid connection.

volume

Pointer of lsm_volume.

write_cache_policy

uint32_t. The write cache policy. Valid values are: * LSM_VOLUME_WRITE_CACHE_POLICY_WRITE_BACK
The storage system will use write back mode if cache hardware
found. * LSM_VOLUME_WRITE_CACHE_POLICY_AUTO
The controller will use write back mode when battery/capacitor
is in good health, otherwise, write through mode. * LSM_VOLUME_WRITE_CACHE_POLICY_WRITE_THROUGH
The storage system will use write through mode. * LSM_VOLUME_WRITE_CACHE_POLICY_UNKNOWN
Plugin failed to detect this setting.

write_cache_status

uint32_t. The status of write cache. Valid values are: * LSM_VOLUME_WRITE_CACHE_STATUS_WRITE_THROUGH * LSM_VOLUME_WRITE_CACHE_STATUS_WRITE_BACK * LSM_VOLUME_WRITE_CACHE_STATUS_UNKNOWN

read_cache_policy

uint32_t. The policy for read cache. Valid values are: * LSM_VOLUME_READ_CACHE_POLICY_ENABLED
Read cache is enabled, when reading I/O on previous unchanged
written I/O or read I/O in cache will be returned to I/O
initiator immediately without checking backing store(normally
disk). * LSM_VOLUME_READ_CACHE_POLICY_DISABLED
Read cache is disabled. * LSM_VOLUME_READ_CACHE_POLICY_UNKNOWN
Plugin failed to detect the read cache policy.

read_cache_status

uint32_t. The status of read cache. Valid values are: * LSM_VOLUME_READ_CACHE_STATUS_ENABLED * LSM_VOLUME_READ_CACHE_STATUS_DISABLED * LSM_VOLUME_READ_CACHE_STATUS_UNKNOWN

physical_disk_cache

Whether physical disk's cache is enabled or not. Please be advised, HDD's physical disk ram cache might not be protected by storage system's battery or capacitor on sudden power loss, you could lose data if a power failure occurs during a write process. For SSD's physical disk cache, please check with the vendor of your hardware RAID card and SSD disk. Valid values are: * LSM_VOLUME_PHYSICAL_DISK_CACHE_ENABLED
Physical disk cache enabled. * LSM_VOLUME_PHYSICAL_DISK_CACHE_DISABLED
Physical disk cache disabled. * LSM_VOLUME_PHYSICAL_DISK_CACHE_USE_DISK_SETTING
Physical disk cache is determined by the disk vendor via
physical disks' SCSI caching mode page(0x08 page). It is
strongly suggested to change this value to
LSM_VOLUME_PHYSICAL_DISK_CACHE_ENABLED or
LSM_VOLUME_PHYSICAL_DISK_CACHE_DISABLED * LSM_VOLUME_PHYSICAL_DISK_CACHE_UNKNOWN
Plugin failed to detect the physical disk status.

flags

Reserved for future use, must be LSM_CLIENT_FLAG_RSVD.

VERSION¶

1.3.

DESCRIPTION¶

Query RAM cache settings for the specified volume.

CAPABILITY¶

LSM_CAP_VOLUME_CACHE_INFO

RETURN¶

Error code as enumerated by 'lsm_error_number'.
* LSM_ERR_OK
On success.
* LSM_ERR_NOT_FOUND_VOLUME
When volume not found.
* LSM_ERR_INVALID_ARGUMENT
When any argument is NULL or invalid flags.
* LSM_ERR_NO_SUPPORT
Not supported.