Hey, are you installing CEPH in your test lab and you screwed it up, or something has gone wrong with your test cluster and you want to start over? Well, the instructions on how to do this are below.
storage
Ceph: Show OSD to Journal Mapping
In Ceph, when you create an OSD (Object Storage Device) you also need to create its Journal, which is where data is initially written before it is flushed to an OSD. Note that too maximize I/O it is suggested to use SSD drives as the journal partitions for your OSDs (see this link for reference). So this … Continue reading Ceph: Show OSD to Journal Mapping
XenServer 6 – Deleting a Storage Repository From the Command Line
Deleting a Storage Repository From the Command Line; So before we get started deleting a Storage Repository, we need to know a few key terms.
In XenServer a Storage Repository is a storage target that contains virtual disks (VDIs) and isos.
XenServer: How to Build and Configure a Dedicated NFS Storage Bond
GodzukiFirst of all let me start this off by saying that there is a lot of information out there on how to setup a dedicated storage interface on XenServer. However, I was unable to find anything specifically related to bonding two unmanaged interfaces and use them for as a dedicated uplink, which is seems rather silly to me as why would you not want to have a highly redundant network connection to your NFS storage. I digress.
Raid Levels Explained and Simplified
First off its important to know that RAID stands for either "Redundant Array of Independent Disks", or more commonly "Redundant Array of Inexpensive Disks". Either way you slice it (pun intended) the basic idea of RAID is to combine multiple hard disks to either increase performance or increase redundancy.
Before I get started its important to introduce the term LUN. A LUN is a logical disk that consists of raw physical disk space. LUNs are created as a basic part of the storage provisioning process. They are presented across a SAN to a server as a single physical disk.
Note that the title of this article is "Raid Levels Explained and Simplified", and when I say Simplified I mean it. I am going to give a brief overview of most of the common RAID levels and then present a weakness and strength.
Linux SAN Disk Managment via DM-Multipath
A little background... Most of the time, I have used the RDAC driver in Linux to manage SAN disks in Linux. The RDAC driver is used to hide the complexity of multiple paths and to present redundant paths as a single path which can be used as you would a standard SCSI / IDE / … Continue reading Linux SAN Disk Managment via DM-Multipath