Monday, January 29, 2018

IOWait reading list

Sunday, January 28, 2018

Ether mining with DwarfPool

Quite happy today that i've finally setup my ether mining rigs on AWS, and joined DwardPool. Checkout my rigs performance at this DwarfPool link :)

It's not profitable with current aws pricing, but hey, it's super fun !!!

Wednesday, December 27, 2017


Storage Basics

Monday, December 25, 2017

Reading list



linux sysAdmin guides:

linux cli tool summary

linux documentation

Thursday, November 30, 2017

DB2 PureScale on AWS?

According to IBM site (link-1, link-2), pureScale minimally needs
  1. the IBM General Parallel File System software to create the DB2 cluster file system on the shared disk;
  2. fast network connectivity (TCPIP allowed since Cancun release).
Notice IBM recently rebranded GPFS to Spectrum Scale, which is conceptually deployable to AWS (, though fine prints may apply (eg. no encryption in ebs, not sure if this is a hard requirement, yet......)

Sounds like it's quite feasible to have pureScale on AWS? will give it a try.

Also, nice guide combing QRepl and across two pureScale clusters.

As for HADR across 2 pureScale clusters, many restrictions apply, with the most significant one being no ROS, followed by (NEAR)SYNC not supported, among many others listed here.

More on GPFS, or should i say spectrumScale, please refer to this link.

Saturday, November 25, 2017

HBase question dumps

Collection of random questions about HBase, for my own reference:

  • Why prefer JBOD over RAID for slave nodes? is it b/c of the underlying assumption of using HDFS? how does HDFS replicates blocks? is it possible that replication fails before a block get replicated? How to recover from such failure, from HDFS standpoint of view?
  • Not directly related to HBase, but what are the pros and cons of different fs mentioned in Chapter 2? (ext3,4, XFS, ZFS....)
  • RPC call between HBase and HDFS, assume version matches, performance concerns? 
  • Best practice on how to avoid memory swap, especially on slaveNode.