Queries a volume group and returns pertinent information.
Logical Volume Manager Library (liblvm.a)
The lvm_queryvg subroutine returns information on the volume group specified by the VG_ID parameter.
The queryvg structure, found in the lvm.h file, contains the following fields:
struct queryvg {
long maxlvs;
long ppsize;
long freespace;
long num_lvs;
long num_pvs;
long total_vgdas;
struct lv_array *lvs;
struct pv_array *pvs;
short conc_capable;
short default_mode;
short conc_status;
unsigned int maxpvs;
unsigned int maxpvpps;
unsigned int maxvgpps;
int total_pps;
char vgtype;
daddr32_t beg_psn;
}
struct pv_array {
struct unique_id pv_id;
char state;
char res[3];
long pvnum_vgdas;
}
struct lv_array {
struct lv_id lv_id;
char lvname[LVM_NAMESIZ];
char state;
char res[3];
}
Field | Description |
---|---|
conc_capable | Indicates that the volume group was created concurrent mode capable if the value is equal to one. |
conc_status | Indicates that the volume group is varied on in concurrent mode. |
beg_psn | Specifies the physical sector number of the first physical partition. |
default_mode | The behavior of this value is undefined. |
freespace | Contains the number of free physical partitions in this volume group. |
lvs | Points to an array of unique IDs, names, and states of the logical volumes in the volume group. |
maxlvs | Specifies the maximum number of logical volumes allowed in the volume group. |
maxpvs | Specifies the maximum number of physical volumes allowed in the volume group. |
maxpvpps | Specifies the maximum number of physical partitions allowed for a physical volume in the volume group. |
maxvgpps | Specifies the maximum number of physical partitions allowed for the entire volume group. |
num_lvs | Indicates the number of logical volumes. |
num_pvs | Indicates the number of physical volumes. |
ppsize | Specifies the size of all physical partitions in the volume group. The size in bytes of each physical partitions is 2 to the power of the ppsize field. |
pvs | Points to an array of unique IDs, states, and the number of volume group descriptor areas for each of the physical volumes in the volume group. |
total_pps | Specifies the total number of physical partitions contained in the volume group. |
total_vgdas | Specifies the total number of volume group descriptor areas for the entire volume group. |
vgtype | Indicates the type of the volume group. If the value of the vgtype field is zero, the volume group is an original volume group. If the value is one, the volume group is a big volume group. If the value is two, the volume group is a scalable volume group. |
The PVName parameter enables the user to query from a descriptor area on a specific physical volume instead of from the Logical Volume Manager's (LVM) most recent, in-memory copy of the descriptor area. This method should only be used if the volume group is varied off. The data returned is not guaranteed to be most recent or correct, and it can reflect a back level descriptor area. The Pvname parameter should specify either the full path name of the physical volume that contains the descriptor area to query or a single file name that must reside in the /dev directory (for example, rhdisk1). The name must represent a raw device. If a raw or character device is not specified for the PVName parameter, the Logical Volume Manager will add an r to the file name in order to have a raw device name. If there is no raw device entry for this name, the LVM returns the LVM_NOTCHARDEV error code. This field must be a null-terminated string of from 1 to LVM_NAMESIZ bytes, including the null byte. If a PVName is specified, the LVM will return the VG_ID to the user through the VG_ID pointer passed in. If the user wishes to query from the LVM in-memory copy, the PVName parameter should be set to null. When using this method of query, the volume group must be varied on, or an error will be returned.
In addition to the PVName parameter, the caller passes the unique ID of the volume group to be queried (VG_ID) and the address of a pointer to a queryvg structure. The LVM will separately allocate enough space for the queryvg structure, as well as the lv_array and pv_array structures, and return the address of the completed structure in the QueryVG parameter passed in by the user. The user is responsible for freeing the space by freeing the lv and pv pointers and then freeing the QueryVG pointer.
Item | Description |
---|---|
VG_ID | Points to a unique_id structure that specifies the volume group to be queried. |
QueryVG | Specifies the address of a pointer to the queryvg structure. |
PVName | Specifies the name of the physical volume that contains the descriptor area to query and must be the name of a raw device. |
The lvm_queryvg subroutine returns a value of zero upon successful completion.
If the lvm_queryvg subroutine fails it returns one of the following error codes:
Item | Description |
---|---|
LVM_ALLOCERR | The subroutine cannot allocate enough space for a complete buffer. |
LVM_FORCEOFF | The volume group has been forcefully varied off due to a loss of quorum. |
LVM_INVALID_PARAM | An invalid parameter was passed into the routine. |
LVM_OFFLINE | The volume group is offline and should be online. |
If the query originates from the varied-on volume group's current volume group descriptor area, one of the following error codes may be returned:
Item | Description |
---|---|
LVM_DALVOPN | The volume group reserved logical volume could not be opened. |
LVM_INV_DEVENT | The device entry for the physical volume specified by the PVName parameter is invalid and cannot be checked to determine if it is raw. |
LVM_MAPFBSY | The volume group is currently locked because system management on the volume group is being done by another process. |
LVM_MAPFOPN | The mapped file, which contains a copy of the volume group descriptor area used for making changes to the volume group, could not be opened. |
LVM_MAPFRDWR | Either the mapped file could not be read, or it could not be written. |
LVM_NOTCHARDEV | A device is not a raw or character device. |
If a physical volume name has been passed, requesting that the query originate from a specific physical volume, one of the following error codes may be returned:
Item | Description |
---|---|
LVM_BADBBDIR | The bad-block directory could not be read or written. |
LVM_LVMRECERR | The LVM record, which contains information about the volume group descriptor area, could not be read. |
LVM_NOPVVGDA | There are no volume group descriptor areas on this physical volume. |
LVM_NOTVGMEM | The physical volume is not a member of a volume group. |
LVM_PVDAREAD | An error occurred while trying to read the volume group descriptor area from the specified physical volume. |
LVM_PVOPNERR | The physical volume device could not be opened. |
LVM_VGDA_BB | A bad block was found in the volume group descriptor area located on the physical volume that was specified for the query. Therefore, a query cannot be done from this physical volume. |