Storage requirements for servers (and applications) is constantly changing. It becomes very important to be able to allocate or deallocate space without interruption to service. This document provides some approaches to discovering new storage, without performing a reconfiguration reboot. This applies to internal and external disk drives as well as virtual disks. Most of the times the disks are detected automatically without doing anything. The devfsadmd daemon will be running in the background and constantly checking for the presence of new hardware, so often times the device will be found right away. Use below methods if the disks are still not visible in the format command.
1. SCSI disks
For any scsi attached jbod device, you can recreate the device trees “on the fly” by reloading the associated driver and re-creating the device trees. In this example, we re-create the device information for a “sd” managed SCSI disk drive in a JBOD array.
# devfsadm -i sd ## reloading associated driver # devfsadm -Cv ## re-creating device trees
Some of the Internal disks in servers use the cfgadm utility to facilitate a disk replacment. Here is an example of replacing an internal failed disk.
# cfgadm -c unconfigure c1::dsk/c1t3d0 ## used prior during removal # cfgadm -c configure c1::dsk/c1t3d0
2. SAS disks
Some SAS connected disk drives are hot swapable via the mpt driver.
# devfsadm -i mpt # devfsadm -Cv
3. iSCSI disks
Even iscsi uses the same technique.
# devfsadm -i iscsi # devfsadm -Cv
4. Fiber channel (FC) disks
Fiber Channel fabric attached devices use the cfgadm utility. In this example, lun 1 of fabric device 203400a0b82fbc5d is added to the server. The lun as seen from the output below is un-configured and needs to be configured to make it seen in the format command.
# cfgadm -al -o show_FCP_dev Ap_Id Type Receptacle Occupant Condition c2::203400a0b82fbc5d,1 disk connected
unconfiguredunknown # cfgadm -c configure c2::203400a0b82fbc5d,1
As a last resort you can use luxadm force_lip command to scan the new FC luns.
# luxadm -e force_lip /dev/cfg/c2 # cfgadm -o show_FCP_dev -al # devfsadm -Cv
5. Veritas volume manager
In case you are using veritas volume manager, you may have to scan the LUNs again using “vxdctl enable” to make them visible under VxVM.
# vxdctl enable