On Sat, Aug 7, 2010 at 1:03 AM, Sebastian 'gonX' Jensen <gonx@xxxxxxxxxxxxxxx> wrote: > On 7 August 2010 00:24, Leonidas Spyropoulos <artafinde@xxxxxxxxx> wrote: >> On Fri, Aug 6, 2010 at 7:32 PM, Sebastian 'gonX' Jensen >> <gonx@xxxxxxxxxxxxxxx> wrote: >>> On 6 August 2010 20:23, Leonidas Spyropoulos <artafinde@xxxxxxxxx> wrote: >>>> Do I have to change the partition ID flag of each partition? >>>> Currently is set to fd (Linux Raid autodetect) for used from mdadm >>>> mkfs.btrfs supports that or needs to be 83 (Linux) ? >>> >>> FD is for mdraid integrated into the Linux kernel. I have mine at 83. >>> It won't hurt to have them at FD, but the kernel will spend extra time >>> as it probes the devices on boot, causing a slight slowdown. >> >> Ok done them id 83 and used 3 devices eventually >> Using raid0 for data and metadata >> # mkfs.btrfs -m raid0 -d raid0 /dev/sdc1 /dev/sdd2 /dev/sde2 >> >> 2 SATA and 1 ATA drive >> I thought that ATA will bottleneck the other 2 drives but seems like I gain >> something from it. >> Using iozone for benchmark: >> # iozone -s 8g -r 1024 -i 0 -i 1 >> with 2 SATA devices and then 3 devices (SATA + ATA): >> KB reclen write rewrite read reread >> 8388608 1024 134869 139607 229146 228800 >> 8388608 1024 135151 139050 233461 235929 >> >> The above is with -o compress option enabled and my cpu topped up on >> 100% cpu (both cores) while test and copy huge data. >> Is it possible I am bottlenecked by my cpu speed? >> AMD Opteron 165 @ 2700 Mhz >> >>>> >>>> On Thu, Aug 5, 2010 at 3:40 PM, Hubert Kario <hka@xxxxxxxxxx> wrote: >>>>> On Thursday 05 August 2010 16:15:22 Leonidas Spyropoulos wrote: >>>>>> Hi all, >>>>>> >>>>>> I want to make a btrfs raid0 on 2 partitions of my pc. >>>>>> Until now I am using the mdadm tools to make a software raid of the 2 >>>>>> partitions /dev/sde2, /dev/sdd2 >>>>>> and then mkfs.etx4 the newly created /dev/md0 device. >>>>>> From performance point of view is it better to keep the configuration of >>>>>> mdadm and just format the /dev/md0 device as btrfs OR >>>>>> delete the raid device and format the 2 partitions /dev/sde2 /dev/sdd2 >>>>>> as a btrfs with 2 devices? >>>>>> mkfs.btrfs /dev/sde2 /dev/sdd2 >>>>> >>>>> Btrfs already supports metadata mirroring when the data is striped. What this >>>>> means, is while the performance should be more-or-less identical to MD RAID0 >>>>> (if it isn't it's a bug), your data is a bit more secure as the metadata >>>>> describing it resides on both drives. Later on it will be possible to selct >>>>> which directories/files should have what level of redundancy. This will allow >>>>> to have ~/work RAID1-ed and ~/videos RAID0-ed while keeping both directories >>>>> on the same partition and filesystem. >>>>> >>>>>> On a sidenote: >>>>>> If I decide to go for raid5 which is not supported currently from mkfs >>>>>> I have to use the mdadm tool anyway, right? >>>>> >>>>> yes, RAID5 code is not in trunk yet. >>>>> >>>>> -- >>>>> Hubert Kario >>>>> QBS - Quality Business Software >>>>> 02-656 Warszawa, ul. Ksawerów 30/85 >>>>> tel. +48 (22) 646-61-51, 646-74-24 >>>>> www.qbs.com.pl >>>>> >>>> >>>> >>>> >>>> -- >>>> Caution: breathing may be hazardous to your health. >>>> -- >>>> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in >>>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>> >>> >>> Regards, >>> Sebastian J. >>> >>> PS. Please try to bottom-post rather than top-post. Here's a link I >>> can advise reading for a clarification on why bottom posting is >>> essential: http://www.caliburn.nl/topposting.html >>> >> Thanks for the heads up about bottom-posting. >> >> >> -- >> Caution: breathing may be hazardous to your health. >> > > It seems odd that you are reaching 100% CPU usage. Maybe it's because > I am on an Intel processor with the integrated crc32c module, but with > metadata and data striping on 2 decent desktop drives (60 MB/s in avg > each on large reads), I don't go much anywhere near 10% CPU usage, and > I have compress-force enabled. I've never tried a stress test iozone, > but if I can still remember it, I will try to run it once I get back > from holidays. Sorry that it doesn't help your problem, but it seems > like it's something else. I really doubt my old Opteron has SSE 4.2 and as mentioned from other users it makes a huge difference. > > I'm assuming you're running the nForce4 chipset. I don't recall it > being there, but is there an AHCI option for S-ATA in the BIOS, rather > than legacy or PATA mode, or something in the lines of that? That > could in theory reduce CPU usage somewhat, but shouldn't really affect > anything before very high transfer speeds. > Yes it's an nForce4 chipset (DFI Expert) And if I recall it's SATA+PATA mode enabled on mine now. I can't be sure since I am working on it from ssh. > And yes, you are bottlenecked if you're running at max CPU usage. I > would try disabling the compress mount option if the above does not > help. After disabling the compress and done the test again it affected the write speed and my CPU wasn't topped up all the time something like 80-90% results with iozone KB reclen write rewrite read reread 8388608 1024 147736 147062 135427 134744 thanks for that > > Regards, > Sebastian J. > The next step is remove the ATA drive and test again with and without compress mount. -- Caution: breathing may be hazardous to your health. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
