On 04/12/12 06:37, Randy Rue wrote:
Looks like upgrading to 8.1x implements a new layer of protection called RLW (RAID protection from Lost Writes). This requires the addition of some metadata to the disk system and after upgrade a background process "rlw_update" runs for some period of time. The trouble is, this process does not "nice" itself as it's meant to when other processes are running. Worse, if it runs at the same time as other "not so nice" processes like de-dupe there can be disastrous performance issues. This problem is exacerbated if disk utilization is high, or if slower disks are used, or if a lot of misaligned traffic is running. Users in the wild have reported the rlw_update process taking several weeks and horrible performance issues during its tenure.
I came across this KB article linked from the support community FAQs https://kb.netapp.com/support/index?page=content&id=3013583 which says:
"Note: 'rlw_upgrading' is just a flag/state, it does not indicate an active process running in the background. This means that there is 'no' background process impacting the storage system's performance. The only performance impact expected is that of scrub, which can be scheduled and stopped by the usual means (for more information, see the 'aggr scrub' man pages). The active process of performing the upgrade is included as part of a RAID scrub. A full manual scrub will not be initiated automatically following an upgrade of Data ONTAP. The aggr scrub status command will indicate if RAID scrubs are currently suspended (not actively running at that moment)."
And I also welcome any feedback from anyone with experience or information to offer. Anyone been in this situation? Anyone running 8.1.2 yet? Anyone have advice on upgrading a significantly busy system?
I upgraded to 8.1.1p1 a few weeks ago, and my root aggregates are now rlw_on, but my other ones are still rlw_upgrading. I haven't noticed any performance problems, but they're not heavily loaded.