> Okay it seems like we don't really have a definitive answer on whether it's OK to use a RAID controller or not and in what capacity. It’s okay to use it if that’s what you have. For new systems, eschew the things. They cost money for something you can do with MD for free and are finicky. Look back on the list a few years for my litany of why I hate the things, all based on personal experience ;) > Passthrough meaning: > > Are you saying that it's OK to use a raid controller where the disks are in non-RAID mode? That’s the best approach in your situation, where you have servers already. > Are you saying that it's OK to use a raid controller where each disk is in its own RAID-0 volume? It’s OK to do that, but there are drawbacks and you should do passthrough instead if you can: * Operational hassles creating those wrappers and tearing them down when deploying OSDs and replacing drives * Firmware updates may be confounded * iostat’s already-marginal stats are confounded * Hassles getting SMART-style stats > > I'm just trying to clarify a little bit. You can imagine that nobody wants to be that user that does this against the documentation's guidelines and then something goes terribly wrong. Dell’s documentation tells you how to set passthrough. If you’ve seen docs that tell you not to, please do send a link as I’d like to see them. Dell qualified a certain unnamed now-EOL SSD, yet I underwent a long and arduous engagement with the manufacturer to fix a firmware design flaw. So I don’t place much stock in Dell recommendations. They REEEEAALLLY likes to stuff RoC HBAs down our throats, and they mark them up outrageously. — aad > > Thanks again, > -Drew > > > -----Original Message----- > From: Anthony D'Atri <aad@xxxxxxxxxxxxxx> > Sent: Thursday, July 11, 2024 7:24 PM > To: Drew Weaver <drew.weaver@xxxxxxxxxx> > Cc: John Jasen <jjasen@xxxxxxxxx>; ceph-users@xxxxxxx > Subject: Re: Repurposing some Dell R750s for Ceph > > > >> >> Isn’t the supported/recommended configuration to use an HBA if you have to but never use a RAID controller? > > That may be something I added to the docs. My contempt for RAID HBAs knows no bounds ;) > > Ceph doesn’t care. Passthrough should work fine, I’ve done that for tends of thousands of OSDs, albeit on different LSI HBA SKUs. > _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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