Author: sotech
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ZFS: Adding a new mirror to an existing ZFS pool
Mirrored vdevs are great for performance and it is quite straight-forward to add a mirrored vdev to an existing pool (presumably one with one or more similar vdevs already): zpool add [poolname] mirror [device01] [device02] [device03] If it’s a two-way mirror you will only have two devices in the above. An example…
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XenServer 6.2: Passing through multiple PCI or PCI Express devices to a Virtual Machine (VM)
Following the previous article on passing through a PCI or PCI Express card to a virtual machine someone asked what the syntax was to pass through multiple devices to a VM. Using our previous system as an example, we run lspci to find each item we want to pass through. Using the same system…
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XenServer 6.2: How to set up passthrough of a PCI or PCI-Express device
This is done by logging in as the root user to your XenServer system via SSH. To see the PCI devices available to your system, enter the following command: lspci Here is an example result: 00:00.0 Host bridge: Advanced Micro Devices, Inc. [AMD/ATI] RD890 Northbridge only dual slot (2×16) PCI-e GFX…
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XenServer 6.2: Which VM type to use for Fedora 20 Live CD installation?
We were asked this today – we have found that the “Other Media” works fine for installation and use, where other options (Red Hat options, for example) don’t work.
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Ubuntu: How to use multiple cores with tar gzip compression
One thing you may have noticed when using the z switch with tar is that the compression can take some time! If you look at your CPU usage, though, you’ll notice that only one core is being utilised to compress the files. In a modern system 4 or 8 cores are common, meaning that…
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Ubuntu: How to add or append a file to an existing tape backup
Sometimes you may with to add files to an existing backup; if you issue a command like: tar -cvf /dev/st0 backupfiles …and the tape is not already set to the end of the previous archive you will over-write any data from the position on the tape. Use the “eom” command to move…
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Ubuntu: Using compression on your tape backups
If you have compressible data you may save space on you tapes by using compression; this comes at a cost of CPU cycles to do the compressing, which can often be a worthwhile tradeoff for a long-term backup. To do this is quite simple – add in the -z switch to your tar command.…
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Ubuntu: Using tar to span a backup across multiple tapes
Following on from the article on writing files to a tape backup, what happens if you want to back up more than what fits on a single tape? Here we want to use the –multi-volume switch, or -M. Use it so: tar -cvMf /dev/[path-to-tape] [backup folder or files] As a working example:…
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How to test and check a HP StoreWorks Ultrium tape drive
With used tape drives falling in price they are now finding their ways into the hands of more home storage enthusiasts; one should be wary about purchasing a tape drive in unknown condition, though, as there’s a good chance that it may be faulty or require servicing. One way to check the status of…
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How to update the firmware of a HP tape drive – StorageWorks Ultrium 448
The quickest and easiest way of updating the firmware is through HP’s Library and Tape Tools – at the time of writing it is available here: http://h18006.www1.hp.com/products/storageworks/ltt/ Click on the “Link to free download” link to acquire the software. Assuming you have the correct drivers for your setup (SCSI/SAS/etc card), the tape…