On Fri, Jul 15, 2016 at 5:21 PM, Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote:
>
>
> On Fri, 15 Jul 2016, Navin P.S wrote:
>
>> Resend ..
>>
>> On Thu, Jul 14, 2016 at 7:55 PM, Navin P.S <navinp1912@xxxxxxxxx> wrote:
>> > Hi,
>> > Can i do dd if=/dev/zero of=/dev/mapper/dmo count=20 ? where dmo is
>> > a dm snapshot origin created through dmsetup command. Instead of
>> > /dev/zero i can write valid devices.
>> >
>> > I could create the dmo through some lvm2 commands.
>
> lvcreate -s
>
>> > Is direct write
>> > with 4k (page size values ) allowed when it is mapped to 2 block
>> > devices in linear mode ?
>> >
>> >
>> > Regards,
>> > -- Navin
>>
>> I'm seeing OOM followed by reboot of host machine.
>> Does this mean this device cannot to exported to containers for writing ?
>
> The snapshot driver requires 32 bytes of memory for one chunk (the chunk
> size is selected with the "-c" switch to lvcreate). You should set system
> memory according to that.
>
> Mikulas
>
>> -- Navin
>>
Are origin devices readonly ?
When i do dd if=/dev/zero of=/dev/mapper/ff count=10, it kills all the
process says OOM.
How do you go about debugging this ? I'm running 4.7.0-rc7+ .
root@vm-xenial-foo:~# dmsetup info
Name: cryptie4-ff
State: ACTIVE
Read Ahead: 256
Tables present: LIVE
Open count: 0
Event number: 0
Major, minor: 251, 0
Number of targets: 2
Name: ff
State: ACTIVE
Read Ahead: 256
Tables present: LIVE
Open count: 0
Event number: 0
Major, minor: 251, 1
Number of targets: 1
root@vm-xenial-foo:~# dmsetup status
cryptie4-ff: 0 102400 linear
cryptie4-ff: 102400 122880 linear
ff: 0 102400 snapshot-origin
root@vm-xenial-foo:~#
free -m
total used free shared buff/cache available
Mem: 7762 2178 3720 358 1864 4920
Swap: 19145 0 19145
--
-- Navin
--
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