[mythtv-users] new drive won't boot

James Linder jam at tigger.ws
Thu Dec 20 02:53:25 UTC 2018

> On 19 Dec 2018, at 11:45 pm, mythtv-users-request at mythtv.org wrote:
>> On 19 Dec 2018, at 4:57 pm, mythtv-users-request at mythtv.org wrote:
>> Greetings Mythizens, I received my replacement drive from Amazon used
>> "rsync" to copy the files from my revived (previously "about to fail")
>> drive, swap the two drives and the box doesn't boot. Unswitch and it boots
>> fine... unmount storage2, and switch drives and the FE finds storage2
>> recordings (on the "rsync'd" drive) then a reboot fails. "fstab" is lookng
>> to mount storage1,2&3, storage directories are back to original form, all
>> default group, granted it doesn't take much, but I'm stumped! What do I
>> need to do to make this drive acceptable to my box? the first of this type
>> of drive worked fine, the odds of getting lemons back to back I woud
>> imagine to be quite high...Please help, TIA Daryl
> Since this is so far OT we may as well have a smile:
> This guy says ?I prayed for a bicycle, but nothing happened?. ? then I
> realized it does not work like this, so I stole a bike and prayed for
> forgiveness?.
> So it is with rsync. (It does not work like. this)
> One *can* fiddle with grub and /etc/fstab, but it will probably take long
> and be painfull. (eg do you have an EFI bios)
> your easiest option is
> 1) boot the bad disk
> 2) run mythconverg_backup.pl If you?ve not used it before 5 min reading is
> needed. Save the backup.
> 3) install the new disk
> 4) install the os, or a newer version if  you want to.
> 5) install mythtv, mariadb, apache2 and php if you want mythweb
> 6) mount the old disk and copy all the. files you want, specially art and
> ts files from myth-place-you-choose
> 7) run mythconverg_restore.pl
> 8) if you do not have same hostname and IP addr then more reading is needed.
> James
> Except my goal is to have the SSD with my OS as the boot drive and the
> three terabyte drives as storage drives, so painful or time consuming as it
> may be this time future disk swaps will be better.

Running the OS from ssd is very non-trivial
With all good practices (WRT ssd trim, swapiness etc) the DB journal and log will use up the ssd within a year and GREAT PAIN results.
SSD is fast to boot and if your ring-buffers are on the ssd you can notice the diff, but otherwise ssd makes no noticable diff.

<very gently he says> the level of error in assuming rsync will make a bootable disk says by all means try, see what you can do, but you are looking at a very hard learning curve ahead.

Newer, cheaper ssds use 2 or 3 cell technology that drops the write life to 1/2 or 1/3. You can get as few as 20 000 write cycles / cell !!

For fixed SATA disks there is no benefit in using UUIDs so your fstab may have entries /dev/sda1 etc etc, that makes copying easier. 
Modern spec, in a flourish of marketing hype, no long specify cell life but total write life ie you can write umpty plonk Pb to your disk and for an ornary desktop machine ssd will outlast mechanical disks. But not for a mythbackend machine.

It is cheap and easy, I use a 1T mechanical dist for all the myth stuff including 2 20G root partitions that are mirrors of each other and a 5T WD passport USB3 for all storage. You can copy one passport to another each week or so without noticing.

In any event you have a lot to figure out on the OS front that only briefly has anything to do with mythtv. Have fun.

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