[CentOS] Btrfs going forward, was: Errors on an SSD drive

Fri Aug 11 18:29:22 UTC 2017
Warren Young <warren at etr-usa.com>

On Aug 11, 2017, at 11:52 AM, hw <hw at gc-24.de> wrote:
> Software RAID with mdadm is a bad idea because
> it comes with quite some performance loss.

That sounds like outdated information, from the time before CPUs were fast enough to do parity RAID calculations with insignificant overhead.

> ZFS is troublesome because it´s not
> as well integrated as we can wish for, booting from a ZFS volume gives you even
> more trouble

Those are both solvable problems, involving less resources than Fedora/Red Hat are throwing at Stratis.  Therefore, we can infer that they don’t *want* to solve those problems.

> it is rather noticeable that ZFS wasn´t designed with
> performance in mind.

You don’t get the vastly superior filesystem durability ZFS offers without a performance hit.  Any competing filesystem that comes along and offers the same features will have the same hit.

If you want burnin’ speed at all costs, use ext4.

> That doesn´t even mention features like checksumming

That is intended to be in Stratis, but not until 3.0, which is not yet even scheduled.

This is part of what I meant by my speculation in a prior post that Stratis won’t be ready for prime time until EL9.  Plan accordingly.

> deduplication, compression

Also Stratis 3.0.

> and the creation of subvolumes (or their equivalent)

That should be possible with the earliest testable versions of Stratis, as LVM2 provides this today:


> It also doesn´t mention
> that LVM is a catastrophy.

I will grant that it’s an utter mess to manage by hand with the current tools.  Fixing that is one of the primary goals of the Stratis project.

Complaining about it on the CentOS list is not the right way to fix it.  If you want Stratis to not suck, they’re targeting the first releases of it for Fedora 28.  

There’s also the GitHub issue tracker.  Let them know what you want Stratis to be; the Stratis developers are not likely to schedule features “properly” if they misunderstand which ones matter most to you.

> I could use hardware RAID

My sense is that the Linux-first hardware RAID card market is shrinking and maybe even dying.

With 10-dumb-SATA motherboards readily available, I think it’s time for hardware RAID to die in Linux, too, if only in the workstation and low-end server segment, where 10-ish drives is enough.

> So far, it´s working fine, but I´d rather switch now than experience
> desaster.

One of your options is to take advantage of the fact that CentOS major releases overlap in support: EL7 will still be supported when EL9 comes out.  All of this should be greatly clarified by then.