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Rich Freeman <rich0 <at> gentoo.org> writes: |
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> > On 27/10/2014 11:24, Mick wrote: |
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> >>> With a caveat: if an ssd dies, it will die suddenly. Without warning. |
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With SSD the most important fact to keep constantly in mind is |
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writing/erasing by blocks due to uniqueness of the hardware. |
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Unfortunately, if you dig deeply, many Solid State Storage devices |
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are organized differently and those hardware differences may impact |
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your SSD_specific implementation details. SSD raid redundancy is |
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something most machines (folks) cannot afford, imho and may be a waist |
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to dis_functional if you employ the same semantics for I/O on the |
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redundant SSD hardware. |
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|
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[1] |
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http://codecapsule.com/2014/02/12/coding-for-ssds-part-6-a-summary-what-every-programmer-should-know-about-solid-state-drives/ |
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> >> In such cases I am prepared to live with the risk of some |
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> >> data loss, on machines where raid is not an option. |
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Wise with a well thought out (planned) recovery/fresh-install strategy. |
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> > Without some form of redundancy that would be your best strategy - |
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> > decent and frequent backups |
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> But yes, backup and RAID are really your only options for SSD failure |
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> as far as I can see it. That and limiting the amount of data that |
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> can't be re-generated. If you just save the world file and all of |
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> /etc you could probably rebuild a Gentoo install fairly quickly on a |
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> new drive, and then you're just left with /home and whatever else you |
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> happen to have installed that sticks stuff in /var that you care |
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> about. |
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Yep. Rich has it exactly right. I'd add /usr/local/* |
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as by design that is where I put most uniqueness in any linux system |
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besides the list above. |
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In fact for small networks, I just identify the directories that I want |
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to preserve. At the least you rsysnc those to a differnet system |
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on the local net, besides a backup, if no raid is underneath. (Triple). |
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Obviously, you have all systems on UPS power......? |
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I'd add any dirs with custom scripts and the kernel files also minimally |
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replicated to another system. A comprehensive list of critical files |
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is fine. Workstations and servers have different lists of critial files; |
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and you can further subdivide the servers by function, to focus |
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on those critical files and directories. So what is on the SSD that is |
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important, just replicate it to a spinning HD on the local net. None |
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of this replaces weekly backups, but give you a tertiary level of |
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recovery redundancy for the important stuff. Triple redundancy is keenly |
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important for all critical stuff; ymmv. |
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Personally, I find max-ram and spinning HD to be the best bang for the |
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buck. But, many folks with older portables are usually really happy with |
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SSD as a replacement (single) drive that is cost effective but needs |
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a network backup. |
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[2] |
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http://serverfault.com/questions/454775/is-post-sudden-power-loss-filesystem-corruption-on-an-ssd-drives-ext3-partition |
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hth, |
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James |