Pre-Install Best Practice (PBP)¶
This how-to sets out to establish Best Practice prior to a Rockstor install. It has grown out of a number of suggestions on the Rockstor forum where problems have been encountered that might otherwise have been avoided. The basic premise is to first ensure that the hardware you are to install Rockstor on is fit for purpose and tested with readily available tools.
Memory Test (memtest86+)¶
The memtest86+ program is derived from the linux kernel itself, the core of the operating system that Rockstor is built on. Memtest86+ v6 is licensed under the GPL v2. This project has more recently undergone a re-write under the v6 version. V6’s code base was originally named PCMemTest, which was in turn based on memtest86+ v5. Technical reference: GitHub memtest86plus.
Memtest86+ Cautionary Note¶
Memtest86+ can place a very intense load on your system, especially if run in the new multi-threaded mode (version 5.01 and newer via F2 on initial start) but a sufficiently cooled system should be able to execute this test indefinitely.
If your system has cooling issues then it may lockup or even sustain damage. Please take care to monitor your system’s temperatures during this test. Version 5.01 and newer have a built-in CPU temperature monitor.
N.B. This memory test will continue indefinitely until you either:
turn off the system (which is safe to do)
press the ESC Key
It is recommended that two full test cycles be completed. But a single full pass of all available tests is better than no memory testing at all!
A single test cycle may well take several hours, depending on the speed of the hardware involved and the size of memory tested.
The official website has Pre-Compiled Bootable ISO images. Along with advise on creating a bootable USB key.
There are limited instances where Rockstors Web-UI may falter, or be confused by a pre-used disks format. Rendering the capability to first wipe these disks via the Web-UI’s Wiping a Partition or Whole Disk inaccessible. On these rare occasions one can simply resource the linux command line tool “wipefs” to achieve the same. Behind the scenes Rockstor’s partition and/or disk wipe procedure executes a “wipefs -a dev-name-here”. Pre-used mdraid members may require additional mdraid configuration removal.
As with all mass delete functions, be extremely certain that you are doing the right thing. This requirement has not now been reported for some time. So do first consider/research carefully if such a command line approach is in fact required.
Past instances of this command line approach to removing pre-use partitioning and formatting has been associated with prior mdraid use and some LVM configurations. Neither of which are supported by Rockstor’s Web-UI.
Darils Boot and Nuke is a popular tool to securely erase HDDs prior to their deployment or disposal. In brief, this tool writes to every part of a disks surface to exercises the entire storage. Akin to Memory Test (memtest86+) this will stress the tested parts of the system; in this case the drives selected for wiping.
Securely remove all data on a per drive basis.
Test the drive/s ability to write to all its available sectors,
It is often the case that a drive is ‘unaware’ of an issue with itself, via the built in SMART system, until an attempts is made to write to a faulty sector. Writes can trigger a drives own built-in ability to swap-in spare/redundant sectors. These spare sectors are a very limited resource, and should not be relied upon.
Note that the zero fill fast option is probably sufficient for testing purposes. There are however many more exotic and official wiping algorithms available. All options will take a considerable amount of time to complete, i.e. in the region of a few hours per drive minimum.
It is not strongly recommended that drives be DBAN tested prior to using them for Rockstor. But this tool can be a valuable resource, especially if a drive’s hardware is suspect. Keep in mind however that this test procedure will stress the drive concerned, and likely its associated cooling.
DBAN Cautionary Note¶
The DBAN program / procedure will Irreversibly Erase/Overwrite all data. Use with extreme caution. Be sure to disconnect all drives that you wish not to be affected before booting/running DBAN.
Due to the comparatively limited write cycles of earlier generation SSDs further wear consideration should be given prior to running DBAN on these devices.
Check Integrity of Downloaded installer¶
It is highly recommended that you check your downloaded installers integrity. If the original download is corrupt then all else that follows is likely to have problems.
ISO is computer-slang/short for ISO9660 which is the International Organization for Standardization official definition of the structure of data on a CD/DVD. If this structure is wrong, or the data contained within is corrupt, then problems will follow. The same is true for our non ISO type installers.
The Rockstor Downloads page has image specific instruction on how to check each type of installer offered via a single simple linux/OSX command line instruction. The test is a checksum validation; made against a tiny matching additional download ending in “sha256”.
A checksum is a mathematical abstraction of a data set, in this case our file, that is unique (near enough anyway). As a result it is possible to establish file corruption by comparing the published checksum with that calculated directly from the downloaded file. This in effect verifies the integrity of the downloaded file and confirms it as free from corruption.