[CentOS] XFS and LVM2 (possibly in the scenario of snapshots)
timo.schoeler at riscworks.net
Thu Dec 10 09:28:40 UTC 2009
>>>> Thanks for your eMail, Ross. So, reading all the stuff here I'm really
>>>> concerned about moving all our data to such a system. The reason we're
>>>> moving is mainly, but not only the longisch fsck UFS (FreeBSD) needs
>>>> after a crash. XFS seemed to me to fit perfectly as I never had issues
>>>> with fsck here. However, this discussion seems to change my mindset. So,
>>>> what would be an alternative (if possible not using hardware RAID
>>>> controllers, as already mentioned)? ext3 is not, here we have long fsck
>>>> runs, too. Even ext4 seems not too good in this area...
>>> I thought 3ware would have been good. Their cards have been praised for
>>> quite some time...have things changed? What about Adaptec?
>> Well, for me the recommended LSI is okay as it's my favorite vendor,
>> too. I used to abandon Adaptec quite a while ago and my optinion was
>> confirmed when the OpenBSD vs. Adaptec discussion came up. However, the
>> question on the hardware RAID's vendor is totally independent from the
>> file system discussion.
> Oh yeah it is. If you use hardware raid, you do not need barriers and
> can afford to turn it off for better performance or use LVM for that matter.
Hi, this ist off list: Could you please explain me the LVM vs. barrier
AFAIU, one should turn off write caches on HDs (in any case), and -- if
there's a BBU backed up RAID controller -- use this cache, but turn off
barriers. When does LVM come into play here? Thanks in advance! :)
>> I re-read XFS's FAQ on this issues, seems to me that we have to set up
>> two machines in the lab, one purely software RAID driven, and one with a
>> JBOD configured hardware RAID controller, and then benchmark and stress
>> testing the setup.
> JBOD? You plan to use software raid with that? Why?!
Mainly due to better manageability and monitoring. Honestly, all the
proprietary tools are not the best.
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