champaka1
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disk alignment warning - Unity300 and Redhat Linux

I am getting an error "alignment is offset by 512 bytes. This may result in very poor performance, (re)-partitioning suggested" when I format any LUN from UNITY300 storage on Redhat Linux. But LUN is already aligned with fdisk command.

Environment details as follows -

1. A direct attached FC Unity300 and HP DL580G9 server + Redhat (RHEL) 7.2

2. FAST cache & FASTVP is enabled

Any storage LUN irrespective of the size giving this error when try to format using mkfs.ext3.

The LUN is already aligned b fdisk/parted and verified by parted tool.

Please see below my steps and command output -

#multipath -ll

mpathd (36006016006214200f43f0f584ce28280) dm-3 DGC     ,VRAID

size=300G features='2 queue_if_no_path retain_attached_hw_handler' hwhandler='1 alua' wp=rw

|-+- policy='service-time 0' prio=50 status=active

| `- 1:0:0:0 sdc 8:32 active ready running

`-+- policy='service-time 0' prio=10 status=enabled

  `- 3:0:0:0 sdd 8:48 active ready running

# fdisk /dev/mapper/mpathd

Welcome to fdisk (util-linux 2.23.2).

Changes will remain in memory only, until you decide to write them.

Be careful before using the write command.

Device does not contain a recognized partition table

Building a new DOS disklabel with disk identifier 0xa0d6a56b.

Command (m for help): n

Partition type:

   p   primary (0 primary, 0 extended, 4 free)

   e   extended

Select (default p): p

Partition number (1-4, default 1):

First sector (65535-629145599, default 65535):

Using default value 65535

Last sector, +sectors or +size{K,M,G} (65535-629145599, default 629145599):

Using default value 629145599

Partition 1 of type Linux and of size 300 GiB is set

Command (m for help): w

The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 22: Invalid argument.

The kernel still uses the old table. The new table will be used at

the next reboot or after you run partprobe(8) or kpartx(8)

Syncing disks.

# partprobe /dev/mapper/mpathd

# mkfs.ext3 /dev/mapper/mpathd1

mke2fs 1.42.9 (28-Dec-2013)

/dev/mapper/mpathd1 alignment is offset by 512 bytes.

This may result in very poor performance, (re)-partitioning suggested.

Discarding device blocks: done

Filesystem label=

OS type: Linux

Block size=4096 (log=2)

Fragment size=4096 (log=2)

Stride=2 blocks, Stripe width=8191 blocks

19660800 inodes, 78635008 blocks

3931750 blocks (5.00%) reserved for the super user

First data block=0

Maximum filesystem blocks=4294967296

2400 block groups

32768 blocks per group, 32768 fragments per group

8192 inodes per group

Superblock backups stored on blocks:

        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,

        4096000, 7962624, 11239424, 20480000, 23887872, 71663616

Allocating group tables: done

Writing inode tables: done

Creating journal (32768 blocks): done

Writing superblocks and filesystem accounting information: done

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hkw1
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Re: disk alignment warning - Unity300 and Redhat Linux

Hi, have you received any response on this?  I also have the same issue and wonder how to resolve this.  Thanks

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