> -----Original Message-----
> From: CentOS [mailto:centos-bounces@xxxxxxxxxx] OnBehalf Of Gregory P.
> Ennis
> Sent: Sunday, February 19, 2017 12:31 PM
> To: centos@xxxxxxxxxx
> Subject: Re: usb drives & Orico ORICO9548U3-BK
>
>
> >
> > I decided to build an archive server for thepurpose of backing up
> > other fedora/centos desktops at theoffice. I built a machine and
> > have installed Centos 7.3 on it with all updatescurrent. I also
> > purchased a 3.0 usb sata drive cabinet (OricoORICO 9548U3-BK) and
> > installed two 5T black WDdrives. There was no problem installing
> > the usb cabinet or the drives. Iformatted each drive with xfs as
> > /dev/sdc and /dev/sdd, and then combined theminto a software mirrored
> > raid with mdadm as /dev/md0.
>
> I've always thought that the perceived wisdom is tonot try and do software
> raid across USB - especially when both drives are atthe other end of the
> same USB cable. Sure USB 3 is faster and there's abetter chance it will appear
> to work at a reasonable speed, but it's notsomething I would contemplate.
>
> >
> > Everything was working perfectly until Iremoved the terminal,
> > keyboard and mouse and tried to reboot themachine. It took a while
> > to figure out, but when the mouse and keyboardwere removed the boot
> > process assigns the usb drives differentlywhich makes /dev/md0
> > created by mdadm fail.
>
> Which means that the drive letters are explicitlymentioned in
> /etc/mdadm.conf - you can change it to be wildcardedor leave mdadm to
> figure it all out itself. See 'manmdadm.conf'.
>
> >
> > My fstab file looks like :
> >
> > /dev/mapper/centos_poar-root / xfs defaults 0
> > 0
> > UUID=f915a354-28bf-4110-bec9-3767ef1fe52c/boot xfs defaults 0
> > 0
> >/dev/mapper/centos_poar-home /home xfs defaults 0
> > 0
> >/dev/mapper/centos_poar-u /u xfs defaults 0
> > 0
> >/dev/mapper/centos_poar-swap swap swap defaults 0
> > 0
> >/dev/sda /u0 btrfs defaults 0
> > 0
> > # entries below were combined into one mirroredraid system
> #/dev/sdc
> >/u1 xfs defaults 0
> > 0
> >#/dev/sdd /u2 xfs defaults 0
> > 0
> >/dev/md0 /u1 xfs defaults 0
> > 0
>
> Another likely issue is that you explicitly mention/dev/sda in the fstab - if the
> drives are re-ordered, then /dev/sda will not bewhat you think it is. It's a
> much better idea to use UUIDs when mounting drives.You can find the UUID
> with
>
> lsblk --fs /dev/sda
>
> BTW, are you really using partitionless disks - isit really /dev/sda and not
> /dev/sda1 ?
>
> >
> >
> > This works perfectly when a usb mouse and a usbkeyboard are attached,
> > but when I remove the mouse and keyboard thesystem will not boot
> > because the usb drives are relabeled as/dev/sda and /dev/sdb.
>
> I would have thought that any SATA drives would havebeen processed
> before the USB drives - certainly it looks that wayon my system. Try going
> through the output of dmesg to see if you can seewhat is really happening
> when in the boot sequence.
>
> >
> >
> > My thought is that if I could force the usbdrives to be labeled as
> > /dev/sdc and /dev/sdd whether the mouse andkeyboard are attached or
> > not, I might be able to fix the problem
>
> It's much easier to make sure you don't explicitlyuse drive letters - because,
> as you've found out, they can change. Usefilesystem labels or UUIDs or disk
> IDs. The disk IDs can be found in /dev/disk/by-idand they should remain the
> same.
>
> P.
>
>-----------------------------------------------------------------
>
> Pete,
>
> Thank you for such excellent help; I appreciate yourwisdom and challenges.
> The machine I am working on is still at the 'lab'stage so everything can be
> changed at this point. I don't have the benefit of much 'perceivedwisdom' in
> that most of my knowledge comes from mistakes I havemade or mistakes
> others on this list have made that Ican learnfrom. So thanks again.
>
> Here are some of my thoughts... right or wrong.
>
> #1. 3.0 USB drives
> I originally performed some testing on a small usbpassport 3T drive and was
> amazed by the response and access times. I stumbled across the Orico
> cabinet during a NewEgg search, and decided to giveit a try. I was even
> more impressed with the response and accesstimes. I decided to attempt a
> mdadm raid on the the Orico and everything hasworked better than
> expected except for the problems I have had withdevice
> assignments. I did have an electrical failure at my home related to
> weather of which the ups powered down after 30minutes that caused one
> of the raid 5T drives to become corrupted. I reformatted the drive and
> rebuilt the raid with mdadm, and everything worked alot better than I
> expected. Iwill only be using this system to store *.tar.gz backup files from
> other systems. What should cause me to fear the USB 3.0 connection.
>
> #2. /etc/mdadm.conf
> The tutorials I read about how to use mdadm did notinclude mdadm.conf,
> and this was not created when I installedmdadm. I will take a look at the
> man pages.... thank you.
>
> #3. UUID's
> Thanks for the suggestion to use names instead ofdevice addresses and
> how to get the names with lsblk --fs /dev/sda. Using this should fix
> my problem of reassignment device names at boottime. Thanks much!!!
>
> #4. Partitionless disks
> I orginally installed Centos 7.3 on an SSD, and theninstalled the hard drives
> subsequently. I noticed that I gained quite a bit of disc space by not using a
> partition. Since the files I will be storing on these discs are large and will only
> be accessed for archive purposes I wanted
> to use as much of the disk as possible. The original google searches
> I made related to using a partitionless disk did notgive me compelling rational
> to use a partition, however I would surely like tohear from you and others
> about this.
>
>
> Thanks again for your help, and instruction!!!!!
>
I kinda did the same thing as you. I bought a 4TB WDElements. Disabled
the sleep timer.
I use UrBackup to backup two local machines, one remote,to my CentOS
server. The WD Elements is backing up the CentOS server as wespeak
(since 9:00AM this morning).
I use a rsync script I
found,https://github.com/laurent22/rsync-time-backup
I started with REAR, but it created a 1TB tar.gz file soI went with the
rsync script. Had to remove the --one-file-system arg.
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