Wow, 1.8 is pretty old these days, as is 2.5 (first release 6 years ago!). I hope you're planning on upgrading past 2.5 once you've upgraded to it. (Honestly, this is all so old at this point you might consider letting your existing system reach EOL on 1.8.x and building a new file system (2.10 is a maintenance branch...) & migrating data.)
Upgrade is possible and relatively easy. Just shut down all your servers, upgrade the Lustre version, then start them as normal. It is a good idea to upgrade your clients at the same time, but you can use 1.8.x clients with 2.5. Not everything works - quota, notably, will not work right - but it is mostly fine. That's the first step of upgrading, and at this point you can easily roll back to 1.8.x. After that, it's more complicated. I won't write it all up for you, but the manual has information on enabling dirdata and doing lfsck namespace, and also on enabling quotas, which is different in 2.5. Once you enable dirdata (even without doing the namespace lfsck, which you should do), you cannot go back to 1.8.x. (It is probably not safe to upgrade beyond 2.5.x without enabling dirdata, nor to downgrade from > 2.5.x to 1.8.x. Those *might* work, but I wouldn't bet my data on it.) Section 17.2 in the manual has the relevant info. - Patrick ________________________________ From: lustre-discuss <lustre-discuss-boun...@lists.lustre.org> on behalf of Richard Chang <rchang.li...@gmail.com> Sent: Monday, February 4, 2019 6:38:57 AM To: lustre-discuss@lists.lustre.org Subject: [lustre-discuss] Upgrade without losing data from 1.8.6 to 2.5.2 and back if necessary Hi, I currently have Lustre 1.8.6 running without much problem. I would like to upgrade to version 2.5.2, but without losing any data. Is it possible to upgrade from 1.8.6 => 2.5.2 and back to older version, in case of any problems. I am unable to find any documentation or any pointers for anyone having done any such thing. I mean, upgrade, and if facing any problem, revert back to older version. Is it possible at all, without losing any data ? Thanks & regards, Rick. _______________________________________________ lustre-discuss mailing list lustre-discuss@lists.lustre.org http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org
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