From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from o.ww.redhat.com (ovpn-117-208.ams2.redhat.com [10.36.117.208]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0B168A0A61 for ; Fri, 12 Oct 2018 12:02:24 +0000 (UTC) References: <20181011142550.GA15437@redhat.com> From: Heinz Mauelshagen Message-ID: <581cfd57-aca0-70f5-b715-f05357e4bbad@redhat.com> Date: Fri, 12 Oct 2018 14:02:22 +0200 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/alternative; boundary="------------A40BB8806DC96661AC6B7FDC" Content-Language: en-MW Subject: Re: [linux-lvm] what is the IOPS behavior when partitions of single disk(raid5 backend) are used in an LVM? Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: To: linux-lvm@redhat.com This is a multi-part message in MIME format. --------------A40BB8806DC96661AC6B7FDC Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Transfer-Encoding: 8bit On 10/11/18 4:31 PM, Emmanuel Gelati wrote: > If you use sdb only for data, you don't have need to use partition on > the disk. Though that's true, keeping 1 partition per disk for each LVM PV adds additional 'visibility' by tools like fdisk/[cs]fdisk, parted etc. showing the partition type to be 'Liinux LVM'. Using the whole disk, blkid or lsblk will provide that information still, e.g. 'blkid --match-token TYPE=LVM2_member'. Heinz > > Il giorno gio 11 ott 2018 alle ore 16:26 David Teigland > > ha scritto: > > On Thu, Oct 11, 2018 at 08:53:07AM +0545, Sherpa Sherpa wrote: > > I have LVM(backed by hardware RAID5) with logical volume and a > volume group > > named "dbstore-lv" and "dbstore-vg" which have sdb1 sdb2 sdb3 > created from > > same sdb disk. > > > sdb                                8:16   0  19.7T  0 disk > > ├─sdb1                             8:17   0   7.7T  0 part > > │ └─dbstore-lv (dm-1)              252:1    0   9.4T  0 lvm  > /var/db/st01 > > ├─sdb2                             8:18   0   1.7T  0 part > > │ └─dbstore-lv (dm-1)              252:1    0   9.4T  0 lvm  > /var/db/st01 > > └─sdb3                             8:19   0  10.3T  0 part > >   └─archive--archivedbstore--lv (dm-0)     252:0    0 10.3T  0 lvm > > > I am assuming this is due to disk seek problem as the same disk > partitions > > are used for same LVM or may be its due to saturation of the disks > > You shouldn't add different partitions as different PVs.  If it's > too late > to fix, it might help to create new LV that uses only one of the > partitions, e.g. lvcreate -n lv -L size vg /dev/sdb2, and then > copy your > current LV to the new one. > > _______________________________________________ > linux-lvm mailing list > linux-lvm@redhat.com > https://www.redhat.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ > > > > -- >   .~. >   /V\ >  //  \\ > /(   )\ > ^`~'^ > > _______________________________________________ > linux-lvm mailing list > linux-lvm@redhat.com > https://www.redhat.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ --------------A40BB8806DC96661AC6B7FDC Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: 8bit
On 10/11/18 4:31 PM, Emmanuel Gelati wrote:
If you use sdb only for data, you don't have need to use partition on the disk.

Though that's true, keeping 1 partition per disk for each LVM PV adds additional
'visibility' by tools like fdisk/[cs]fdisk, parted etc. showing the partition type to be 'Liinux LVM'.

Using the whole disk, blkid or lsblk will provide that information still,
e.g. 'blkid --match-token TYPE=LVM2_member'.

Heinz


Il giorno gio 11 ott 2018 alle ore 16:26 David Teigland <teigland@redhat.com> ha scritto:
On Thu, Oct 11, 2018 at 08:53:07AM +0545, Sherpa Sherpa wrote:
> I have LVM(backed by hardware RAID5) with logical volume and a volume group
> named "dbstore-lv" and "dbstore-vg" which have sdb1 sdb2 sdb3 created from
> same sdb disk.

> sdb                                8:16   0  19.7T  0 disk
> ├─sdb1                             8:17   0   7.7T  0 part
> │ └─dbstore-lv (dm-1)              252:1    0   9.4T  0 lvm  /var/db/st01
> ├─sdb2                             8:18   0   1.7T  0 part
> │ └─dbstore-lv (dm-1)              252:1    0   9.4T  0 lvm  /var/db/st01
> └─sdb3                             8:19   0  10.3T  0 part
>   └─archive--archivedbstore--lv (dm-0)     252:0    0  10.3T  0 lvm

> I am assuming this is due to disk seek problem as the same disk partitions
> are used for same LVM or may be its due to saturation of the disks

You shouldn't add different partitions as different PVs.  If it's too late
to fix, it might help to create new LV that uses only one of the
partitions, e.g. lvcreate -n lv -L size vg /dev/sdb2, and then copy your
current LV to the new one.

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  /V\
 //  \\
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