herbyscrub
New Member
You can very easily create shared storage using cheap older generation enterprise hardware from eBay. Most people just don't know how to get around the 1Gbps ethernet bottleneck. Simplest way would be to buy some 4Gbps FC HBA cards for $20 and ptp. Plenty of interesting reading you can do on this subject.
PwnyExpress
New Member
Infiniband 10Gig cards are also coming down in price too. Switches for that stuff is now in the sub $1K range in the secondary market
herbyscrub
New Member
Lol yeah, most of things are still out of hobby range. But the 4Gbps stuff is super cheap right now. We're upgrading to EMC VNX at the office, was thinking of pulling one of the old FC enclosures, but not really sure how loud it is.
elohkcalb
New Member
Hmm... this reminds me of an article that I/O Flood posted on their blog last year.
"Hardware raid or software raid? Our take on the great religious debate" (http://blog.ioflood.com/?p=26)
"Hardware raid or software raid? Our take on the great religious debate" (http://blog.ioflood.com/?p=26)
Last edited by a moderator:
Another great discussion that has been going on forever in every forum I know.
Hardware raid when setup properly outperforms software raid in every aspect beside cost.
Software raid is for personal usage and for dev work I would never use it for production servers regardless of usage or load.
All linux users need to make sure if you're using hardware raid to set your i/o scheduler to either deadline or noop for performance increases as your not using the full benefits of the card when the linux kernel by default is set to cfq
Hardware raid when enable in the linux kernel to use either deadline or noop with push all the workload from the cpu to the raid card.
Also as a reminder that not all raid cards support the trim function from SSD so if you are building a system with ssd make sure you do the research.
Hardware raid when setup properly outperforms software raid in every aspect beside cost.
Software raid is for personal usage and for dev work I would never use it for production servers regardless of usage or load.
All linux users need to make sure if you're using hardware raid to set your i/o scheduler to either deadline or noop for performance increases as your not using the full benefits of the card when the linux kernel by default is set to cfq
- noop is often the best choice for memory-backed block devices (e.g. ramdisks) and other non-rotational media (flash) where trying to reschedule I/O is a waste of resources
- as (anticipatory) is conceptually similar to deadline, but with more heuristics that often improve performance (but sometimes can decrease it)
- deadline is a lightweight scheduler which tries to put a hard limit on latency
- cfq tries to maintain system-wide fairness of I/O bandwidth
Hardware raid when enable in the linux kernel to use either deadline or noop with push all the workload from the cpu to the raid card.
Also as a reminder that not all raid cards support the trim function from SSD so if you are building a system with ssd make sure you do the research.
Last edited by a moderator:
In a Software RAID setup, what happens if the OS crashes, bugs out or is simply reinstalled? What impact does hard reset of server have over Software RAID, and for that matter, Hardware RAID? I have seen hardware RAID with BBU. Is that some kind of a safeguard against hard reset?
It depends on how Software RAID is setup. It's usually quite stable these days with lots of advanced features.
BBU is backup battery unit. It's used when your server goes out of power and gives it time from the battery to write data stored in the cache to the actual disks. It's needed when you want to use the cache in the RAID card.
turfhosting
New Member
It's very obvious hardware raid is the winner here. Its faster and way more reliable..
Shouldn't of even been a question -.-
Shouldn't of even been a question -.-
Last edited by a moderator:
Both have advantages and disadvantages, however my personal opinion is that if you can not afford spending 500-1000$ on a good hardware raid card, it would be better to stick with software RAID. In my experience so far, I never had a software RAID fail and at least 3 times a hardware RAID fail, where once the data was completely lost, as the new RAID card did not recognize the old array. Of course, a good and premium RAID card, with all the fancy features that are now offered is much better than software RAID performance wise, however I don't understand all the hate towards SW RAID, as it still gets the job done, probably even better than half of the HW cards on the market.