From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin ESTRABAUD Subject: Re: strange partition table and slow speeds Date: Fri, 04 Jan 2013 15:45:08 +0000 Message-ID: <50E6F904.80808@mpstor.com> References: <28361073.8.1355777233170.JavaMail.root@zimbra> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Alex Pientka Cc: Roy Sigurd Karlsbakk , linux-raid@vger.kernel.org, Phil Turmel List-Id: linux-raid.ids You simply don't have a partition table on those disks. This is not a problem. Disks do not specifically need to be partitioned= =2E In a way, it's like if you did "mkfs.ext3 /dev/sdX" instead of=20 "mkfs.ext3 /dev/sdXn". The entire drive (including the space for the=20 partition table) can be expected to be used. The fact that it was there "before" and not anymore could be a fluke,=20 some of the superblock may have only been written later on. The fact that it is not there will not affect performance in any way,=20 and the array is likely the same as it always was. Regards, Ben. On 17/12/12 21:16, Alex Pientka wrote: > I want to understand why my partition table is suddenly different > moving it from one system to a different one. This happened after I > moved the 6 drives from one system to the new system. > > Is this the reason why I suddenly have such bad performance? > Alex > > > On Mon, Dec 17, 2012 at 3:47 PM, Roy Sigurd Karlsbakk wrote: >> why would you want to use partitions for such a RAID in the first pl= ace? >> >> ----- Opprinnelig melding ----- >>> That brings up the question: Any reason to get the partition table >>> fixed up? Is this just a cosmetic issue? >>> Alex >>> >>> >>> On Mon, Dec 17, 2012 at 12:41 PM, Phil Turmel >>> wrote: >>>> [Top-posting repaired. Please don't.] >>>> >>>> On 12/17/2012 12:26 PM, Alex Pientka wrote: >>>>> On Mon, Dec 17, 2012 at 12:18 PM, Phil Turmel >>>>> wrote: >>>>>> Hi Alex, >>>>>> >>>>>> On 12/17/2012 09:17 AM, Alex Pientka wrote: >>>>>> >>>>>> [trim /] >>>>>>> /dev/md0: >>>>>>> Version : 1.1 >>>>>> ^^^^^ >>>>>> You've deliberately chosen a metadata version that places the >>>>>> superblock >>>>>> at sector 0 of the given device. If that is a whole disk, it >>>>>> overwrites >>>>>> the partition table. The default metadata is v1.2 (which places >>>>>> the >>>>>> superblock at offset 4k) for this very reason. >>>>> I assume upgrading to v1.2 is not possible. The only other way >>>>> would >>>>> be to fail every raw device (one-by-one) and then create the fd >>>>> partition on it, correct? >>>> You could put the array back on partitions if you like. I'd make a >>>> complete backup, zero the superblocks, and use --create >>>> --assume-clean >>>> to switch to v1.2 in place (with due care to maintain the device >>>> order >>>> and data offsets). >>>> >>>> (Save the output of "mdadm -E /dev/sdXX" for each member device >>>> before >>>> you start.) >>>> >>>> However, that fdisk can't understand the partition table shouldn't >>>> be >>>> hurting anything, so I wouldn't make it a priority. >>>> >>>> BTW, partition type 'fd' is deprecated along with v0.90 metadata, = as >>>> it >>>> only impacts kernel non-initramfs autoassembly, and that only work= s >>>> with >>>> DOS partition tables and v0.90 metadata. >>>> >>>> Phil >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-rai= d" >>> in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> -- >> Vennlige hilsener / Best regards >> >> roy >> -- >> Roy Sigurd Karlsbakk >> (+47) 98013356 >> roy@karlsbakk.net >> http://blogg.karlsbakk.net/ >> GPG Public key: http://karlsbakk.net/roysigurdkarlsbakk.pubkey.txt >> -- >> I all pedagogikk er det essensielt at pensum presenteres intelligibe= lt. Det er et element=E6rt imperativ for alle pedagoger =E5 unng=E5 eks= essiv anvendelse av idiomer med xenotyp etymologi. I de fleste tilfelle= r eksisterer adekvate og relevante synonymer p=E5 norsk. > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid"= in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html