NetApp Bug-Burt 393877- Spike

High Read Latency Spike Causes Outage to underlying Virtual Infrastructure.

a.       These variables are set at the loader prompt (Note: this settings are platform dependent).
b.      LOADER-A> setenv raid_vol_readio_res_count 6230
c.       LOADER-A> setenv raid_mirror_readio_res_count 7702
d.      LOADER-A> setenv wafl_pw_limit_percent 12

The 'raid_vol_readio_res_count' and 'raid_mirror_readio_res_count' increase the resource count available for RAID.  By default the partial write limit is 50% of the resources count.

Setting 'wafl_pw_limit_percent ' reduces this value to mitigate a partial write workload from dominating the system.

This is only a partial fix and may not completely eliminate the issue seen. (Random Read Spike).  It is for this reason an upgrade to DOT 8.1.3 upon release is still the long term recommendation".

VM Client Disconnecting Issue:
a.       http://kb.vmware.com/kb/51306
b.      https://kb.netapp.com/support/index?page=content&id=2010823

Nutanix and MapReduce

So Nutanix relased the latest NOS 3.0 with all rich features. One of them that acutally hit me was the offline compression.

Mapreduce techniques to essentially figure out which data has gone cold and then compress it. the compression only occurs when the system is idle and data is cold, and determining when data is cold is left up to the user (e.g. after one day or after one hour). This technique is based on Google’s snappy compression library and hits a nice balance between high-speed & reasonable compression rate.