* [linux-lvm] raid0 - no performance increase?? [not found] <269f632e-591e-56c3-a3be-31ac6060f73f.ref@yahoo.co.uk> @ 2020-10-10 16:52 ` lejeczek 2020-10-11 20:15 ` Bastian Blank 0 siblings, 1 reply; 2+ messages in thread From: lejeczek @ 2020-10-10 16:52 UTC (permalink / raw) To: LVM general discussion and development Hi guys, I have a simple raid0 lvm comprising of two NVME devices. I'd expect performance of such a volume to be higher than a "regular" volume ran of a single NVME, but simple dbench shows such raid0 volume to the same "slow" as a single NVME volume. The system is a Centos 8 with 5.8.14-1.el8.elrepo.x86_64 and default kernels. raid0: #Str #DStr Stripe Type Devices 2 2 64.00k raid0 0_rimage_0(0),0_rimage_1(0) 1 1 0 linear /dev/nvme0n1(0) 1 1 0 linear /dev/nvme1n1(0) Care to share your thoughts? I'll be grateful. many thanks, L ^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [linux-lvm] raid0 - no performance increase?? 2020-10-10 16:52 ` [linux-lvm] raid0 - no performance increase?? lejeczek @ 2020-10-11 20:15 ` Bastian Blank 0 siblings, 0 replies; 2+ messages in thread From: Bastian Blank @ 2020-10-11 20:15 UTC (permalink / raw) To: linux-lvm On Sat, Oct 10, 2020 at 05:52:32PM +0100, lejeczek wrote: > I have a simple raid0 lvm comprising of two NVME devices. > I'd expect performance of such a volume to be higher than a > "regular" volume ran of a single NVME, but simple dbench > shows such raid0 volume to the same "slow" as a single NVME > volume. Why do you think? What is dbench anyway? Linear access is not going to be faster, as it is dominated by latency. Please use fio with _random_ reads or writes and a useful queue depth. Also, what do you mean with slow? 500k IOPS? Bastian -- War is never imperative. -- McCoy, "Balance of Terror", stardate 1709.2 ^ permalink raw reply [flat|nested] 2+ messages in thread
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2020-10-10 16:52 ` [linux-lvm] raid0 - no performance increase?? lejeczek
2020-10-11 20:15 ` Bastian Blank
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