Which is better for 4x300Gb SAS 15K - RAID 5 or RAID 10?

Question

RAID

We are currently building a new server, a small dispute broke out over the choice of the type of raid array.

Server HP DL180 G6 with 2x Intel Quad Core E5620 , 16Gb of memory and 4x300Gb SAS 15K , intended for large MySQL database (currently ~20Gb and in the near future it will increase by a couple of gigs).

CTO and admin say that hardware RAID 5 is better, they say there is a bit more space and good speed, and I (the lead programmer) tend to think that RAID 10 is better, because. with an equal number of disks, the read speed will be greater, plus a dozen will rebuild faster if one of the disks fails. Who is right and why?

PS Which of the options is easier to expand in the future?

Answer 1

We use RAID10 on 6 SAS disks on a highly loaded project.
1) RAID10 is easy to repair, and 1..2 disks break per year
2) SAS - these disks can withstand combat loads, but a replica that lives on RAID0 of 4 SATA always lags behind.
3) All RAID arrays are soft (Linux) - it turns out more reliable
4) ZFS in RAID10 is a very good option for FreeBSD

Answer 2

ZFS in RAID10

Answer 3

RAID10 is faster. Feel faster. Do not read the rest of the arguments, you yourself know them.
RAID5 on 3 disks is slower than RAID1 in terms of total write speed.
The implementation doesn't matter. Be it ZFS, hardware RAID, btrfs or md. In its class, 10s are always faster.

Answer 4

same server
freebsd 8.2 + raid10
easy administration and good speed

Answer 5

take 10 sata screws for 2TB in the sixth raid + hotspare, it will be faster and you won’t have to expand for a long time.

Answer 6

I strongly doubt that 10xSATA will be faster than 4xSAS 15k, especially since the size is not critical at all. Maybe a proof?

Answer 7

What will be stored in the database? What is the nature of the load?
If you have a controller with cache memory and a battery, then you will not see a fundamental difference in linear writing / reading. If your database is characterized by a lot of random writes, RAID10 will be preferable.
As far as I understand, the advantage of RAID5 in lower overhead costs for disk space is not critical for you, since the base, even taking into account the growth, fits quite well on RAID10.
With regards to expandability for the future, RAID5 has an advantage, since you can add one disk to the array, in RAID10 - only an even number of disks, but the expansion procedure itself for RAID5, as a rule, takes more time.

Answer 8

It is unlikely that my comment is relevant, but "HP DL180 G6", if it is hotswap, then it goes at least with HP SmartArray P212, you can change it to HP SA P41x
And yes, RAID 10 is better than RAID 5 in 99% of cases.