Block checksum via MDRAID?
by Gionatan Danti
Hi list,
I just learned about Stratis, and it is a very exciting project! The
idea of ZFS-like features, while preserving proper layering in the I/O
stack, in a single, simple package is really cool.
I read the Stratis PDF documentation and, if I understand it properly,
you plan to use dm-integrity to checksum blocks on the I/O device. I
wonder if you considered extending current MDRAID code to integrate
checksumming capability: in this manner, you not only "shave off" a I/O
layer (no need of dm-integrity on the single block devices), but *any*
new MD array become automatically checksum-protected.
Some years ago, this very idea was heavily debated on MDRAID mailing
list. At the time BTRFS looked "almost ready", so the MDADM maintainer
decided that disk's own hardware ECC was enough to protect from the most
likely problems. Maybe this can be right time to revisit this position?
Thanks.
--
Danti Gionatan
Supporto Tecnico
Assyoma S.r.l. - www.assyoma.it
email: g.danti(a)assyoma.it - info(a)assyoma.it
GPG public key ID: FF5F32A8
6 years, 8 months
Stratis 0.1 released
by Andy Grover
Stratis 0.1 is now available.
This is the initial alpha release. It is feature-complete for basic
expected functionality, including creating pools from blockdevs,
creating filesystems from a pool, renaming, listing, deletion, and
recreating running state from on-disk metadata. It has not yet been
tested extensively.
* It it recommended to use a scratch system or VM for running Stratis,
with no valuable data.
* The use of other tools that use device-mapper, such as LVM, on a test
system is best avoided.
* The use of small blockdevs (total size under 5 GiB) to create a pool
is best avoided, since Stratis doesn't yet gracefully handle running out
of space.
* Once stratisd is run and then exited (e.g. with a ctrl-C), a reboot is
required before it can successfully run again.
The easiest way to try Stratis is to install Fedora 25 or 26 (x86_64)
and add our COPR test repo:
`dnf copr enable grover/stratis`
`dnf install stratis stratisd`
Then, run 'stratisd' as root in one terminal, and interact with it using
the 'stratis' command-line tool in another root terminal. See "man
stratis' for more info.
You may give feedback by:
* Sending an email to this list
* Opening an issue against either
https://github.com/stratis-storage/stratisd or
https://github.com/stratis-storage/stratis-cli
* Joining the #stratis-storage irc channel on irc.freenode.net.
The truly brave can find release tarballs and build instructions for the
five Stratis components here:
https://github.com/stratis-storage/stratisd/releases
https://github.com/stratis-storage/stratis-cli/releases
https://github.com/stratis-storage/into-dbus-python/releases
https://github.com/stratis-storage/dbus-signature-pyparsing/releases
https://github.com/stratis-storage/stratisd-client-dbus/releases
Thanks -- Regards -- Andy
6 years, 8 months