> On 01 Aug 2016, at 19:30, Michelle Sullivan <miche...@sorbs.net> wrote: > > There are reasons for using either…
Indeed, but my decision was to run ZFS. And getting a HBA in some configurations can be difficult because vendors insist on using RAID adapters. After all, that’s what most of their customers demand. Fortunately, at least some Avago/LSI cards can work as HBAs pretty well. An example is the now venerable LSI2008. > Nowadays its seems the conversations have degenerated into those like Windows > vs Linux vs Mac where everyone thinks their answer is the right one (just as > you suggested you (Borja Marcos) did with the Dell salesman), where in > reality each has its own advantages and disadvantages. I know, but this is not the case. But it’s quite frustrating to try to order a server with a HBA rather than a RAID and receiving an answer such as “the HBA option is not available”. That’s why people are zapping, flashing and, generally, torturing HBA cards rather cruelly ;) So, in my case, it’s not about what’s better or worse. It’s just a simpler issue. Customer (myself) has made a decision, which can be right or wrong. Manufacturer fails to deliver what I need. If it was only one manufacturer, well, off with them, but the issue is widespread in industry. > Eg: I'm running 2 zfs servers on 'LSI 9260-16i's... big mistake! (the ZFS, > not LSI's)... one is a 'movie server' the other a 'postgresql database' > server... The latter most would agree is a bad use of zfs, the die-hards > won't but then they don't understand database servers and how they work on > disk. The former has mixed views, some argue that zfs is the only way to > ensure the movies will always work, personally I think of all the years > before zfs when my data on disk worked without failure until the disks > themselves failed... and RAID stopped that happening... what suddenly > changed, are disks and ram suddenly not reliable at transferring data? .. > anyhow back to the issue there is another part with this particular hardware > that people just throw away… Well, silent corruption can happen. I’ve seen it once caused by a flaky HBA and ZFS saved the cake. Yes. there were reliable replicas. Still, rebuilding would be a pain in the ass. > The LSI 9260-* controllers have been designed to provide on hardware RAID. > The caching whether using the Cachecade SSD or just oneboard ECC memory is > *ONLY* used when running some sort of RAID set and LVs... this is why LSI > recommend 'MegaCli -CfgEachDskRaid0' because it does enable caching.. A good > read on how to setup something similar is here: > https://calomel.org/megacli_lsi_commands.html (disclaimer, I haven't parsed > it all so the author could be clueless, but it seems to give generally good > advice.) Going the way of 'JBOD' is a bad thing to do, just don't, > performance sucks. As for the recommended command above, can't comment > because currently I don't use it nor will I need to in the near future... but… Actually it’s not a good idea to use heavy disk caching when running ZFS. Its reliability depends on being able to commit metadata to disk. So I don’t care about that caching option. Provided you have enough RAM, ZFS is very effective caching data itself. > If you (O Hartmann) want to use or need to use ZFS with any OS including > FreeBSD don't go with the LSI 92xx series controllers, its just the wrong > thing to do.. Pick an HBA that is designed to give you direct access to the > drives not one you have to kludge and cajole.. Including LSI controllers with > caches that use the mfi driver, just not those that are not designed to work > in a non RAID mode (with or without the passthru command/mode above.) As I said, the problem is, sometimes it’s not so easy to find the right HBA. > So moral of the story/choices. Don't go with ZFS because people tell you its > best, because it isn't, go with ZFS if it suits your hardware and > application, and if ZFS suits your application, get hardware for it. Indeed, I second this. But really, "hardware for it" covers a rather broad cathegory ;) ZFS can even manage to work on hardware _against_ it. Borja. _______________________________________________ freebsd-performance@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-performance To unsubscribe, send any mail to "freebsd-performance-unsubscr...@freebsd.org"
