Am 17.09.2013 20:11, schrieb cov...@ccs.covici.com:
> Volker Armin Hemmann <volkerar...@googlemail.com> wrote:
>
>> Am 17.09.2013 09:20, schrieb Grant:
>>> I'm convinced I need 3-disk RAID1 so I can lose 2 drives and keep
>>> running. I'd also like to stripe for performance, resulting in
>>> RAID10. It sounds like most hardware controllers do not support
>>> 6-disk RAID10 so ZFS looks very interesting.
>>>
>>> Can I operate ZFS RAID without a hardware RAID controller?
>>>
>>> >From a RAID perspective only, is ZFS a better choice than conventional
>>> software RAID?
>>>
>>> ZFS seems to have many excellent features and I'd like to ease into
>>> them slowly (like an old man into a nice warm bath). Does ZFS allow
>>> you to set up additional features later (e.g. snapshots, encryption,
>>> deduplication, compression) or is some forethought required when first
>>> making the filesystem?
>>>
>>> It looks like there are comprehensive ZFS Gentoo docs
>>> (http://wiki.gentoo.org/wiki/ZFS) but can anyone tell me from the real
>>> world about how much extra difficulty/complexity is added to
>>> installation and ongoing administration when choosing ZFS over ext4?
>>>
>>> Performance doesn't seem to be one of ZFS's strong points. Is it
>>> considered suitable for a high-performance server?
>>>
>>> http://www.phoronix.com/scan.php?page=news_item&px=MTM1NTA
>>>
>>> Besides performance, are there any drawbacks to ZFS compared to ext4?
>>>
>> do yourself three favours:
>>
>> use ECC ram. Lots of it. 16GB DDR3 1600 ECC ram cost you less than 170€.
>> And it is worth it. ZFS showed me just how many silent corruptions can
>> happen on a 'stable' system. Errors never seen neither detected thanks
>> to using 'standard' ram.
>>
>> turn off readahead. ZFS' own readahead and the kernel's clash - badly.
>> Turn off kernel's readahead for a visible performance boon.
>>
>> use noop as io-scheduler.
> How do you turnoff read ahead?
>
set it with blockdev to 8 (for example). Doesn't turn it off. Just makes
it none-obstrusive.
