Search Results for: raid

On SSDs – Lifespans, Health Measurement and RAID

Solid State Drive (SSD) have made it big and have made their way not only in desktop computing but also in mission-critical servers. SSDs have proved to be a break-through in IO performance and leave HDD far far behind in terms of Random IO performance. Random IO is what most of the database administrators would […]

Aligning IO on a hard disk RAID – the Theory

Now that flash storage is becoming more popular, IO alignment question keeps popping up more often than it used to when all we had were rotating hard disk drives. I think the reason is very simple – when systems only had one bearing hard disk drive (HDD) as in RAID1 or one disk drive at […]

The perils of uniform hardware and RAID auto-learn cycles

Last night a customer had an emergency in selected machines on a large cluster of quite uniform database servers. Some of the servers were slowing down in a very puzzling way over a short time span (a couple of hours). Queries were taking multiple seconds to execute instead of being practically instantaneous. But nothing seemed […]

RAID throughput on FusionIO

Along with maximal possible fsync/sec it is interesting how different software RAID modes affects throughput on FusionIO cards. In short conclusion, RAID10 modes really disappoint me, the detailed numbers to follow. To get numbers I run

test with 16KB page size, random read and writes, 1 and 16 threads, O_DIRECT mode. FusionIO cards are […]

fsyncs on software raid on FusionIO

As soon as we get couple FusionIO cards, there is question how to join them in single space for database. FusionIO does not provide any mirroring/stripping solutions and totally relies on OS tools there. So for Linux we have software RAID and LVM, I tried to followup on my post How many fsync / sec […]