Bad Linux storage performance, in comparison with Windows on the same machine

Solution 1:

It is quite unliked that you are limited by IRQ service time if using only two SATA disks. Rather, it is very probable that the slow IO speed you see is the direct result of the MegaRAID controller disabling the disk's own, private DRAM caches which, for SSD, are critical to obtain good performance.

If you are using a PERC-branded MegaRAID card, you can enable the disk's private cache via omconfig storage vdisk controller=0 vdisk=0 diskcachepolicy=enabled (I wrote that from memory and only as an example; please check with the omconfig CLI reference

Anyway, be sure to understand what this means: if disk cache is enabled when using consumer (ie: non-power-protected) SSD, any power outage can lead to data loss. If you host critical data, do not enable the disk cache; rather, buy enterprise-grade SSD which cames with powerloss-protected writeback cache (eg: Intel S4510).

If, and only if, your data are expendable, then feel free to enable the disk's internal cache.

Some more reference: https://notesbytom.wordpress.com/2016/10/21/dell-perc-megaraid-disk-cache-policy/