[Clas12_first_exp] Fwd: Re: [Clas_offline] preparations for new Hall B /volatile

[Latifa Elouadrhiri]

FYI as discussed today at the meeting



-------- Forwarded Message --------
Subject: 	Re: [Clas_offline] preparations for new Hall B /volatile
Date: 	Wed, 15 Jan 2020 15:24:29 +0000
From: 	Nathan Baltzell <baltzell at jlab.org>
To: 	clas12 software <clas12_software at jlab.org>, CLAS-OFFLINE 
<clas_offline at jlab.org>, HPS-SOFTWARE <hps-software at slac.stanford.edu>, 
prad at jlab.org <prad at jlab.org>



Hello All,

So far there’s been no complaints to hold this up.  Unless that changes, 
*the plan is to do the flip tomorrow, Thursday, January 16, at 10:00 AM*.

Here’s the final details:

1. All our existing, top-level /volatile directories and their data will 
be remounted/renamed with “_old” suffixes.  These will remain available 
for at least 1 month, but read-only.  For example:

/volatile/clas12 -> /volatile/clas12_old
/volatile/clas/clase1 -> /volatile/clas/clase1_old
/volatile/hallb/prad -> /volatile/hallb/prad_old

2. The new filesystem will replace the old one, with all top-level 
directories and their permissions intact, but empty with *no* contents.

3. We then move any data we want from the old filesystem to the new one, 
recreate directory structures, etc.

After no less than one month, the old filesystem will be deleted/drained 
(with a reminder email a ~week in advance) and returned to the disk pool 
for a further increase.  To expedite that, us deleting our data on the 
old filesystem in advance will help.

-Nathan



> On Jan 13, 2020, at 20:14, Nathan Baltzell <baltzell at jlab.org 
> <mailto:baltzell at jlab.org>> wrote:
>
> Hello Everyone,
>
> JLab's Scicomp is almost ready to switch Hall-B's Lustre filesystems 
> at /volatile to new hardware, which should give us a 
> *very* significant increase in disk space.
>
> However, the proposed transition will not be completely transparent to 
> users with existing data on /volatile.  See below for details.
>
> The earliest possible date for this is January 16, Thursday of this 
> week.  The next option would be next Tuesday, January 20, after the 
> long weekend.
>
> This transition ideally applies to all these, and everything they 
> contain, in one shot:
>
> /volatile/clas12
> /volatile/hallb
> /volatile/clas
>
> The proposed transition minimizes downtime and system overhead, but 
> will *not* automatically replicate anyone's existing /volatile data to 
> the new filesystem:
>
> 1.  The old /volatile directories above will be renamed/remounted as 
> /volatile-old (or a similar name), become *read-only*, and remain 
> readable for ~one month (similar to our current lifetime on /volatile).
>
> 2.  The new /volatile filesystem will replace the old one, with all 
> quota-level directories and permissions replicated, but 
> sub-directories left to us to recreate as needed.
>
> 3.  We can then copy data from /volatile-old to /volatile if we want 
> to, or leave it there (and keep reading it) until it is deleted in a 
> ~month.
>
> I'm not aware of any production accounts currently running long batch 
> workflows using /volatile.  It will be good to minimize this 
> transition's impact (and get a huge increase in disk space), so please 
> let me know if you have any considerations, concerns, etc about this.
>
> There will be a followup email with the final date and details ...
>
> Regards,
> Nathan

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