DRBD and the speed difference between the hard drives servers
87 views
Skip to first unread message
Osvaldo T Crispim Filho
Jan 25, 2016, 5:11:53 AM1/25/16
to ganeti
DRBD and the speed difference in the hard drives .
I will have problems to use hard drives with different read and write speeds between servers ?
I have a DELL which has 10,000 rpm disk and i am installing an HP server to backup that uses a different disk 7,500 rpm.
I will have problems to use hard drives with different read and write speeds between servers ?
I have a DELL which has 10,000 rpm disk and i am installing an HP server to backup that uses a different disk 7,500 rpm.
candlerb
Jan 25, 2016, 6:17:20 AM1/25/16
to ganeti
On Monday, 25 January 2016 10:11:53 UTC, Osvaldo T Crispim Filho wrote:
I will have problems to use hard drives with different read and write speeds between servers ?
No, but writes to replicated storage will go at the speed of the slowest device.
Note in addition that drbd will slow things down anyway, even with the same speed at both sides: any write to local disk will not be confirmed complete until it has also been completed on the remote disk, and that involves a network round-trip.
I understand that ganeti uses drbd protocol C:
tschend
Jan 26, 2016, 4:42:55 AM1/26/16
to ganeti
2 cents from my side:
Going with protocol B would speed things up (memory copy) but in case of a double failure (power outage) you would loose data.
To improve things maybe you can get two cheap SSDs and use flashcache / bcache in front of the raid array in write back mode.
This will improve speed a lot.
Phil Regnauld
Jan 26, 2016, 6:44:39 AM1/26/16
to gan...@googlegroups.com
tschend (thomas.schend) writes:
> 2 cents from my side:
>
> Going with protocol B would speed things up (memory copy) but in case of a
> double failure (power outage) you would loose data.
>
> To improve things maybe you can get two cheap SSDs and use flashcache /
> bcache in front of the raid array in write back mode.
> This will improve speed a lot.
It'd be interesting to get a more detailed description of that setup!
> 2 cents from my side:
>
> Going with protocol B would speed things up (memory copy) but in case of a
> double failure (power outage) you would loose data.
>
> To improve things maybe you can get two cheap SSDs and use flashcache /
> bcache in front of the raid array in write back mode.
> This will improve speed a lot.
Phil
candlerb
Jan 26, 2016, 9:59:11 AM1/26/16
to ganeti
On Tuesday, 26 January 2016 15:27:55 UTC+5:45, tschend wrote:
To improve things maybe you can get two cheap SSDs and use flashcache / bcache in front of the raid array in write back mode.This will improve speed a lot.
That can improve the speed of a RAID array - but I'm not sure the OP said they were using a RAID array at all.
Is it possible to accelerate DRBD using an SSD?
Reply all
Reply to author
Forward
0 new messages