2 Commits

Author	SHA1	Message	Date
Jonathan Brassow	2e0740f7ef	RAID: Add writemostly/writebehind support for RAID1 ... 'lvchange' is used to alter a RAID 1 logical volume's write-mostly and write-behind characteristics. The '--writemostly' parameter takes a PV as an argument with an optional trailing character to specify whether to set ('y'), unset ('n'), or toggle ('t') the value. If no trailing character is given, it will set the flag. Synopsis: lvchange [--writemostly <PV>:{t|y|n}] [--writebehind <count>] vg/lv Example: lvchange --writemostly /dev/sdb1:y --writebehind 512 vg/raid1_lv The last character in the 'lv_attr' field is used to show whether a device has the WriteMostly flag set. It is signified with a 'w'. If the device has failed, the 'p'artial flag has priority. Example ("nosync" raid1 with mismatch_cnt and writemostly): [~]# lvs -a --segment vg LV VG Attr #Str Type SSize raid1 vg Rwi---r-m 2 raid1 500.00m [raid1_rimage_0] vg Iwi---r-- 1 linear 500.00m [raid1_rimage_1] vg Iwi---r-w 1 linear 500.00m [raid1_rmeta_0] vg ewi---r-- 1 linear 4.00m [raid1_rmeta_1] vg ewi---r-- 1 linear 4.00m Example (raid1 with mismatch_cnt, writemostly - but failed drive): [~]# lvs -a --segment vg LV VG Attr #Str Type SSize raid1 vg rwi---r-p 2 raid1 500.00m [raid1_rimage_0] vg Iwi---r-- 1 linear 500.00m [raid1_rimage_1] vg Iwi---r-p 1 linear 500.00m [raid1_rmeta_0] vg ewi---r-- 1 linear 4.00m [raid1_rmeta_1] vg ewi---r-p 1 linear 4.00m A new reportable field has been added for writebehind as well. If write-behind has not been set or the LV is not RAID1, the field will be blank. Example (writebehind is set): [~]# lvs -a -o name,attr,writebehind vg LV Attr WBehind lv rwi-a-r-- 512 [lv_rimage_0] iwi-aor-w [lv_rimage_1] iwi-aor-- [lv_rmeta_0] ewi-aor-- [lv_rmeta_1] ewi-aor-- Example (writebehind is not set): [~]# lvs -a -o name,attr,writebehind vg LV Attr WBehind lv rwi-a-r-- [lv_rimage_0] iwi-aor-w [lv_rimage_1] iwi-aor-- [lv_rmeta_0] ewi-aor-- [lv_rmeta_1] ewi-aor--	2013-04-15 13:59:46 -05:00
Jonathan Brassow	ff64e3500f	RAID: Add scrubbing support for RAID LVs ... New options to 'lvchange' allow users to scrub their RAID LVs. Synopsis: lvchange --syncaction {check|repair} vg/raid_lv RAID scrubbing is the process of reading all the data and parity blocks in an array and checking to see whether they are coherent. 'lvchange' can now initaite the two scrubbing operations: "check" and "repair". "check" will go over the array and recored the number of discrepancies but not repair them. "repair" will correct the discrepancies as it finds them. 'lvchange --syncaction repair vg/raid_lv' is not to be confused with 'lvconvert --repair vg/raid_lv'. The former initiates a background synchronization operation on the array, while the latter is designed to repair/replace failed devices in a mirror or RAID logical volume. Additional reporting has been added for 'lvs' to support the new operations. Two new printable fields (which are not printed by default) have been added: "syncaction" and "mismatches". These can be accessed using the '-o' option to 'lvs', like: lvs -o +syncaction,mismatches vg/lv "syncaction" will print the current synchronization operation that the RAID volume is performing. It can be one of the following: - idle: All sync operations complete (doing nothing) - resync: Initializing an array or recovering after a machine failure - recover: Replacing a device in the array - check: Looking for array inconsistencies - repair: Looking for and repairing inconsistencies The "mismatches" field with print the number of descrepancies found during a check or repair operation. The 'Cpy%Sync' field already available to 'lvs' will print the progress of any of the above syncactions, including check and repair. Finally, the lv_attr field has changed to accomadate the scrubbing operations as well. The role of the 'p'artial character in the lv_attr report field as expanded. "Partial" is really an indicator for the health of a logical volume and it makes sense to extend this include other health indicators as well, specifically: 'm'ismatches: Indicates that there are discrepancies in a RAID LV. This character is shown after a scrubbing operation has detected that portions of the RAID are not coherent. 'r'efresh : Indicates that a device in a RAID array has suffered a failure and the kernel regards it as failed - even though LVM can read the device label and considers the device to be ok. The LV should be 'r'efreshed to notify the kernel that the device is now available, or the device should be 'r'eplaced if it is suspected of failing.	2013-04-11 15:33:59 -05:00