no password for ssh

src:
- http://www.thegeekstuff.com/2008/11/3-steps-to-perform-ssh-login-without-password-using-ssh-keygen-ssh-copy-id/
 https://docs.google.com/file/d/0B543p5wfySTQRkw2VTNkcmtBcDg/edit (prtpdf)

notes:
- 15'2/26:
   [TODO] need to confirm whether it works?

Git introduction

src:
- http://git-scm.com/book/en/v2/Getting-Started-Git-Basics
  https://docs.google.com/file/d/0B543p5wfySTQY2l2c3JDbkw5U3M/edit (mypdf)


notes:
15'2/26:
- Git use snapshot instead of file backup
- offline support
- 3 states : committed, modified, staged (loops)
- [TODO] check the operation & setup

STONITH

src:
[S01] http://en.wikipedia.org/wiki/STONITH

reference:
[R01] http://yimu1023.blog.163.com/blog/static/362522822008621511567/

content:
- [S01]
STONITH ("Shoot The Other Node In The Head" or "Shoot The Offending Node In The Head"), sometimes called STOMITH ("Shoot The Other Member/Machine In The Head"), is a technique for fencing in computer clusters.^[1]

Fencing is the isolation of a failed node so that it does not cause disruption to a computer cluster. As its name suggests, STONITH fences failed nodes by resetting or powering down the failed node.

Multi-node error-prone contention in a cluster can have catastrophic results, such as if both nodes try writing to a shared storage resource. STONITH provides effective, if rather drastic, protection against these problems.

Single node systems use a comparable mechanism called a watchdog timer. A watchdog timer will reset the node if the node does not tell the watchdog circuit that it is operating well. A STONITH decision can be based on various decisions which can be customer specific plugins

notes:
15'2/25:
[S01]
- an idea to prevent multi brain issue in a cluster. Need to check the further implementation [TODO]

Multi-Volume Filesystem

src:
https://sort.symantec.com/public/documents/sfha/6.0/linux/productguides/html/sf_admin/ch25s01.htm

content:

About multi-volume file systems

Veritas File System (VxFS) provides support for multi-volume file systems when used in conjunction with the Veritas Volume Manager. Using multi-volume support (MVS), a single file system can be created over multiple volumes, each volume having its own properties. For example, it is possible to place metadata on mirrored storage while placing file data on better-performing volume types such as RAID-1+0 (striped and mirrored). The volume must be in the same disk group as the volume set, and it cannot already be a member of another volume set.

The MVS feature also allows file systems to reside on different classes of devices, so that a file system can be supported from both inexpensive disks and from expensive arrays. Using the MVS administrative interface, you can control which data goes on which volume types.

Note:

Multi-volume file system support is available only on file systems using disk layout Version 7 or later.

notes:
15'2/25:
- a concept that meta & user data could be separated but not sure whether the user data could be
(1) splitted and saved in different volume? [TODO]
(2) duplication in different volume? [TODO]