Rich Mingin (PLUG) via plug on 21 Jul 2024 12:33:31 -0700


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Re: [PLUG] System won't boot after failed upgrade from Ubuntu 23.10 to 24.04

Generally in RAID systems, all the member disks or partitions will be treated as being the size of the smallest member. A simple stripe of 4 2TB disks and 4 4TB disks will give you 8x2 usable space, not 4x2+4x4. If you replace the small disks with larger ones, the available space may increase. This is highly dependent on *what* is managing/controlling your array.

There are a *very* few RAID types that not only benefit from, but often *call for* dissimilar disks. Specifically “RAID4” stripes data across a number of lower performance member disks, and keeps checksums and metadata on a single high performance disk. This was found in almost all cases to be inferior to other RAID levels, and I would not recommend arrays other than simple mirrors for any modern desktop.

On Sun, Jul 21, 2024 at 15:28 Bill Patterson <bill.patterson1@comcast.net> wrote:
I was actually thinking more in a theoretical sense. When you combine two resources of different powers, the result is not necessarily additive. I know that the RAID concept stands for redundant arrays of inexpensive disks and has several different mapping possibilities to enable a marginal amount of additional storage capacity to provide for recovery from any particular error. What I don't know is whether the disks can be mixed in sizes with proportional results.

This is really just the point for a ponderance of pondering.


Bill Patterson


On July 21, 2024 2:09:02 PM EDT, "Keith C. Perry" <kperry@daotechnologies.com> wrote:
Bill,

Quick question, is this for your system drive or data?


On July 21, 2024 1:27:52 PM EDT, "Rich Mingin (PLUG) via plug" <plug@lists.phillylinux.org> wrote:
Yes. How much depends on the RAID type. The best corner case is a RAID1 on Linux with one HDD and one SSD. This will always write at HDD speeds, since a write has to be confirmed to both/all targets before it is complete, but a read can be covered by the first valid mirror to respond.

In other RAID profiles, it’s all downsides. It’s really not something you want to do.


On Sun, Jul 21, 2024 at 10:54 Walt Mankowski via plug <plug@lists.phillylinux.org> wrote:
I don't have any idea. I assume you meant to ask the mailing list and
not me personally, so I've cc'd them.

Walt

On Sun, Jul 21, 2024 at 10:31:46AM -0400, Bill Patterson wrote:
> I have a theoretical question: if you mix solid state drives with regular hard drives in a RAID environment will the slow one slow down the faster one?
>
> Bill
>
> On July 20, 2024 10:59:15 AM EDT, Walt Mankowski via plug <plug@lists.phillylinux.org> wrote:
> >On Mon, May 27, 2024 at 06:49:55AM -0400, Walt Mankowski via plug wrote:
> >> As for the backups, yes, I have them, but the reinstall won't be
> >> easy. For one thing, my case isn't easy to work on. For another, both
> >> the smallish SSD and the big HHD are both RAIDed. Even to expand /usr
> >> is going to be tricky, since I had a hard time getting that setup 6
> >> years ago and I don't remember now how I did it.
> >>
> >> I suppose I could replace the old RAIDed SSDs with a single much
> >> bigger SSD, then either restore to that or do a fresh install of
> >> Ubuntu onto it.
> >>
> >> Or I could spend a few $100 and get a brand new box, and restore to
> >> that instead.
> >
> >I ended up doing a combination of all of this. I spent about $400 on a
> >new box and did a fresh install of Ubuntu 24.04. I was able to restore
> >most of my data from my backups, but it turned out I wasn't backing up
> >a lot of the data that was on my big RAID 1 array. (I know, I know,
> >don't judge me.)
> >
> >So last week I pulled one of the drives from my old dead machine and
> >put it in a drive enclosure. It was a little tricky mounting it
> >because it had also been LVMed as well as RAIDed, but it wasn't as bad
> >as I feared and in about 10 minutes of Googling I had it mounted.
> >
> >I'm getting warnings about once a day that I'm running a degraded RAID
> >array, but aside from that it's working great. Thanks again to
> >everyone who offered help and encouragement.
> >
> >The computer I ended up getting is a Beelink mini-pc. It's really
> >tiny -- maybe the size of 2-3 slices of Wonder Bread -- but comes with
> >a bunch of ports and is quite peppy. My config with a 500 GB SSD and
> >32 GB of RAM came to under $400 with shipping.
> >
> >It ships with Win11 Pro but Ubuntu installed easily. There's a known
> >issue with the Wifi drivers, but it didn't affect me since I'm using
> >wired ethernet. (There's a workaround online.) I'm happy with it so
> >far and at that price point I'm thinking of buying another to have a
> >proper Win11 box for my ham radio adventures.
> >
> >Walt
> >___________________________________________________________________________
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___________________________________________________________________________
Philadelphia Linux Users Group         --        http://www.phillylinux.org
Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce
General Discussion  --   http://lists.phillylinux.org/mailman/listinfo/plug
___________________________________________________________________________
Philadelphia Linux Users Group         --        http://www.phillylinux.org
Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce
General Discussion  --   http://lists.phillylinux.org/mailman/listinfo/plug