Software raid how to optimize software raid on linux using. That card doesnt seem to be a real raid5 card, despite what intel says. The biggest difference between raid 5 and raid 10 is how it rebuilds the disks. This can be somewhat compensated for by really good raid cards with large caches that will allow the software to believe the write is done, though the raid controller has not yet committed it to disk. A year with nvme raid 0 in a real world setup eteknix. I am running windows 7 x64 and i have tried both the intel 8. Raid 10 needs 4 disks to write the data and raid 5 needs 3 disks to write the data. I have recently noticed that write speed to the raid array is very slow.
A single 115 mb file takes 33 seconds to transfer to the raid volume from an eide drive on. To calculate raid performance select the raid level and provide the following values. Raid 5 slow sequential write speed solutions experts. Fortunately, it is easy to build a software raid 5 in windows 8. Home featured a year with nvme raid 0 in a real world setup. Increase software raid5 write speed raid openmediavault. Write operations are slower on a raid 1 because a write operation is not complete until data is written to all of the disks. Compared to other raid levels we have a higher write overhead in raid 5. Of course, raid 1 requires a great deal of extra disk space double the usable space you need, so you pay for each approach in different ways. The performance is great in raid 10 but in raid 5 performance is slow due to redundancy of disks. Raid 5 has good failure resistance and better security. You didnt tell us the type of raid adapter youre using hardware, software, etc but if its a hardware raid array you might have a write cache. Im trying to convert my system over to raid 1 to abandon raid 5.
We have tried reformatting the logical drive and it still has the same performan. Mirroring is writing data to two or more hard drive disks hdds at the same time if one disk fails, the mirror image preserves the data from the failed disk. Have you ever tried to rebuild a failed 1tb disk from parity in raid 5. Raid 5 read is a little slower than raid 10 because the data are not always in the same disks.
Normally with crappy drives and crappy controllers without write cache enable, i expect always around 35mb sec on sequential writes, as this array is a large storage for backups there is no better option now than raid 5 with hot spare, especially with skyrocketing prices od disks due to the floods in thailand. Im running 4x wd black 2tb through my motherboards sata 2 3. Solucion velocidad escritura lenta en raid 5 intel raid 5. Need some help with slow raid 5 performance on my 3ware 9500s controller. Slow write speeds on raid 5 setup toms hardware forum. Proliant e200 slow write on raid 5 hewlett packard. The xor calculations are barely a blip in the processor for even halfway modern systems. A lot of software raids performance depends on the.
Slow write performance with raid5 on z170 and z270. Raid 5 requires the use of at least 3 drives, striping the data across multiple drives like raid 0, but also has a parity distributed across the drives. Nonboot virtual disks of any supported raid level by. Mdadm is linux based software that allows you to use the operating system to create and handle raid arrays with ssds or normal hdds. Software vs hardware raid performance and cache usage. The other raid 5 array on the same controller with 3 segate 1tb drives also shows similarly poor write performance. This means that a raid 5 array will have to read the data, read the parity, write the data, and finally write the parity. The overhead is worse if the raid 5 is software based. I set up a raid 5 volume with it and found that read write performance was much worse than i would have expected.
Understanding raid performance at various levels storagecraft. Hardwarebased raid 5 is better, but still not as fast as raid 1. Raid 5 has fairly slow write speeds, but impressive read speeds, raid 0 has impressive read and write speeds but obviously isnt redundant. Parity raid adds a somewhat complicated need to verify and re write parity with every write that goes to disk. Raid 1 vs raid 5 is mostly a question of what is more important to you in terms of performance and cost raid 1 is a mirrored pair of disk drives.
I know its software raid, but i was expecting a bit more performance than that. In general, software raid offers very good performance and is relatively easy to maintain. Only when the application is write intensive, raid 10 is better. I am certain that there is something wrong, since the write speed to this volume is extremely slow. Proliant e200 slow write on raid 5 im working with a e200 storage controler with 128mb bbc and firmware level at 1.
I heard the raid card making single, long beeps, usually during shut down. Jan 29, 2018 parity calculations is what kills raid 5 and raid 6 for write performance, and unless your workload is a readonly andor b highly sequential raid 10 will outperform raid 5 or raid 6particularly in a random readwrite scenario raid 10 easily outperforms raid 5 and raid 6. Add some cache to that controller and you will get good performance for many typical file access patterns. Processor and ram were irst raid 5 is slow as hell because its not a proper raid solution, real hardware raid has a writeback cache,these days with a small flash memory and a few years ago with ram and a battery backup. My system is down at the moment, but ill experiment at my end as well, and update here if i manage to improve it. I installed an lsi logic megaraid sata raid controller, and set up a 3drive raid 5 volume. Intel raid 5 poor write performance what fixed mine. The raid 5 array is made up of the 3 2tb drives listed above which currently achieves read speeds of around 340mbs and write speeds of 280mb s. Raid 1 makes only 314gb of storage available but every file you write is written back to both disks slowing things down but increasing the level the tolerance for failure. From what i hear, raid 1 isnt horrible, but raid 5 is the biggest loser when it. While its true raid 5 writes are slower than say, raid 10, theyre not that slow. Slow write to raid 5 hewlett packard enterprise community. Windows 7 has arbitrary restrictions on the available raid levels, and it was impossible to create a level 5 raid without windows server.
I am concerned about raid 5 write performance and would like some input from others. Well duh, raid 5parity is slower for writes because of the xor calculations. New raid 5, slow write speeds softraid support forum. Storage spaces in windows 10 extremely slow i have a pair of 4tb drives joined in a twoway mirror to give a singe 4tb storage space. Riad 5 on intel rapid storage technology extremely slow write speeds i setup raid 5 on my z68 motherboard using intels rapid storage technology. Im mildly concerned about the write penalties but its not going to be doing a ton of write io so im not really worried. I restored to a previous version earlier than yesterday, and the same problem existed. Solved slow data copypaste speeds in windows 10 windows 10 forums really the most frustrating thing i have ever encountered on a pc that took me over 2 weeks to find. Raid 10 only reads the surviving mirror and stores the copy to the new drive you replaced. So i deleted that raid set and again made and raid 5. Microsoft storage spaces is hot garbage for parity storage. Three years ago i warned that raid 5 would stop working in 2009.
Is there anything i can do to improve read write speed. Hello daveosac, in my case they are still investigating the problem, so i prefer to be cautious until they give me a formal response. On the software raid side you can try to take turns, kicking one disk. Im running atto at the moment and i see 3kbs write and 5 kbs read on 0. Raid 6 is like raid 5, but the parity data are written to two drives. Slow sata speed on windows 10 solved windows 10 forums. Mac pro 5,1 extremely slow mojave raid0 macrumors forums. Ok we have a hp proliant ml370 g6 brand new with server 2008 and 6gb ram we have 2 drives in raid 1 for os working fine. With current technology, raid 5 write is as fast as raid 10 as parity data are calculated transparently in general. May 30, 2017 up until windows 8, software raid in windows was a mess. I set up a raid 5 array on a windows server 2016 machine more on that later using the exact same drives it was able to push 1 mbs.
I have done a bios update of the motherboard to the latest stable revision, is there a firmware update for the ich10r that i can perform. Slow write speed raid 5 promise forum promise technology. Using crystalmark, the max read speed were seeing is 12mbs, with write as. Is it a journalling file system, that will slow the writes down even more because the journal needs to. Software raid how to optimize software raid on linux. If you are using a very old cpu, or are trying to run software raid on a server that already has very high cpu usage, you may experience slower than normal performance, but in most cases there is nothing wrong with using mdadm to create software raids. I have recently migrated my file server over to a hp microserver. I am told rst raid5 works fine when controlled by mdadm in linux rather than the windows software which is especially irritating. Storage spaces in windows 10 extremely slow microsoft. The dell poweredge raid controller perc s is an economical raid solution for the dell poweredge systems. Processor and ram were formula for raid 5 write performance is nx4. We have 6 drives in raid 5 which have abysmally slow writes to them, i mean just very very slow.
Jul 15, 2014 i created the raid from the bios utility selecting 64kb size i had option of selecting 64 and 128 but the utility reccomended 64kb in case of raid 5. I created the raid from the bios utility selecting 64kb size i had option of selecting 64 and 128 but the utility reccomended 64kb in case of raid 5. There are a few things that can slow down array rebuild process concurrent io on the same disk, high cpu usage. Software raid is also a very interesting option for highavailability redundant server systems. The benchmark will report a 10x slowness when it is 1 checking the raid for consistency, 2 writing the checksums, 3 refeshing the raid redundancy, 4 have a driver that is not compatible with the os, or 5 having sector read issues. To check if there was something wrong with the drives, i created a six drive raid 0 array and got speeds of 1145mbs write and read. In this article we will see in some detail why there is a larger penalty for writing to raid 5 disk systems. Sure enough, no enterprise storage vendor now recommends raid 5.
Software raid hands this off to the servers own cpu. Volume, raid 1, raid 0, raid 5, raid 10 linux raid. So the formula for raid 5 write performance is nx4. The problem with software raid 5 6 is that writes often trigger a readmodifywrite, which in turn slow down the disks considerably. Low raid 5 write performance on p5q deluxe anandtech forums. Hello, i recently got a used pegasus3 r6 and am getting slower write speeds than expected in raid 5. Slow disk writes in raid1 and raid5 page 2 dell community. The server has two 1tb disks, in a software raid 1 array, using mdadm.
Raid 10 vs raid 5 learn 17 most valuable performance. Intel rst on compatible motherboards for sata ssds, hard drives, and nvme drives if vroc is unavailable. The read speeds are sufficiently fast but writing is very slow. Speed test with blackmagic is resulting in read and write speeds of about 400mbs, what is nearly three times the speed of a single disk.
Jun 22, 2005 the overhead is worse if the raid 5 is software based. Raid 5 is not recommended for the pi during testing it choked the whole system while performing writes. I know from experience on similar and probably slower drives, that raid 5 is not that slow, even on spinning disks. The server has two 1tb disks, in a software raid1 array, using mdadm. Building a raid 5 from the same disks is reducing read spead to 270mbs what i was suggesting, but write speed is going down to only 90mbs what is slower than a single disk. I am using 6 wd10eacs drives 6 x 1tb in a raid 5 partition, using the onboard intel raid controller ich10r. Your usual read and write operations are virtually unchanged from normal operations. Read performance with raid5 is 300mbs but write performance is only 15mbs.
When i migrated simply moved the mirrored disks over, from the old server ubuntu 9. Data loss cannot be managed and unacceptable in raid 10 if the information is written in only 1 disk. Just upgraded back to windows 10 and followed the link, getting about 200mbps from my sata 6 to my usb 3 drive. If my calculations are correct then that would mean the write speed was at about 74mbs. Riad 5 on intel rapid storage technology extremely slow. This means that a raid 5 array will have to read the data, read the parity, write the data and finally write the parity. Doing a new write, what data does the raid5set have to read from the disks, the data is not yet on the disks.
In the event of a single drive failure, data is pieced together using the parity information stored on the other drives. Linux software raid for secondary drives not where the os itself is located a selection of dedicated raid controller cards, which are best if you need advanced raid modes 5, 6, etc intel vroc on compatible motherboards for nvme drives. Dec 17, 2018 ive got a linux md raid system, with 5 drives and i can get 400 mbs of writes from a simple dd write test. That means it requires at least 4 drives and can withstand 2 drives dying simultaneously. I am just going to go through the things i did to achieve those speeds.
I read write performance is equal to worst disk but that probably only applies to hardware raid, not software. Raid 5 performance took a nose dive recently, that is not indicative of how raid 5 has historically performed, and the biggest culprits to investigate for this slow down is intels drivers and windows configuration. Slow write speed on intel raid 5 6xred 4tb hard disk. Btw raid 5 i do think that going software raid 5 was a bad choice, i should have gone with 2 3tb drives in raid 1 on the other hand the drive mostly deals with media so speed is not the biggest factor here. It was working fine under windows 8, however ever since i upgraded to windows 10, the speed of both read and write has dropped to 4mbsec or less read or write. I also used a disk speed testing software called black. Find answers to raid 5 is much slower than single drive, is it normal.
Read speed is as fast as raid 5, but write speed is slower than raid 5 due to the additional parity data that have to be calculated. Currently only getting between 315mb writing between arrays 1025mbs writing from mb attached hd to either array this seems very slow. I will say that with 48 hdds in raid5 on a good areca or similar controller you will get much better sequential read write speeds than a single drive of the same type can provide. Command to see what scheduler is being used for disks. Slow disk access after raid 5 rebuild anandtech forums. By using ahci straight on the motherboard with linux software. I am getting very slow write speeds raid 1 and raid 0 striping and mirroring. The drives are 4 samsung f4eg 2tb in raid 5, 128k stripe, with updated firmware.
Create a hardened raspberry pi nas alex ellis blog. Once in windows i formatted the raid unit with a 20gb partition and write speed was really slow 10 mbs max, even after waiting raid to be completely constructed it took several hours after. At first i thought it was just poor performance under raid 1 but it is occuring with raid 0 although not as bad. Help i run a raid 5 array with 7x 72gb 15k sas hp disks in my dl380 g6, i made a windows 10 vm for testing purposes, the read speed of the array is just fine, but the write. Could anybody provide some advise on how to resolve the seemingly slow write. Raid 5 read performance will be good but writing is going to be slow also the 5400 rpm speed is not going to assist much with the slow writing but i realize there isnt too much you can do here outside of slightly faster residential grade drives like raptors. Ive personally seen a software raid 1 beat an lsi hardware raid 1 that was using the same drives.
Up until windows 8, software raid in windows was a mess. A bbuenabled hardware raid controller can coalesce multiple writes in a single disk accesstransaction, greatly improving performance. Right now we have compared a 3 years old hp server raid 5 and the new one raid 5 too. Parity calculations is what kills raid 5 and raid 6 for write performance, and unless your workload is a readonly andor b highly sequential raid 10 will outperform raid 5 or raid 6particularly in a random read write scenario raid 10 easily outperforms raid 5 and raid 6. Slow write performance with raid5 on z170 and z270 chipsets. Slow disk writes in raid1 and raid5 we are also seeing unacceptable performance of a dell server with h310 and 2. Very slow write speed on my pci sata raid 5 anandtech. Since raid 5 uses striping, read operations occur in parallel and are very fast. Creating raid 5 striping with distributed parity in linux.
Hi, im using n40l with software raid5 mdadm 4x3tb xfs and openmediavault. Slow disk writes in raid1 and raid5 dell community. To illustrate, i have attached a screenshot with benchmarks on several volumes that i completed using xbench. I am having issues with the write speed of a newly created raid 5. Raid 5 3 3 minimum number of physical disks in a raid 10 4 4. Reads and writes on raid 5 since raid 5 uses striping, read operations occur in parallel and are very fast. Slow write speed corrected by ssd recondition operation. Increase software raid5 write speed jan 26th 20, 7.