DR group logs on FATA drives

[meno]

Hi,

I have two EVA 8400 in two locations (two fabrics).
I have 24 DR groups in synchronous replication mode. All virtual disks are on FC drives.
Can I use FATA drives for DR Group logs?

I consider using FC drives for DR logs that it is wasting FC drives. I have no intersite link down during last six month.

Marian

[Torsten.]

AFAIR this is not supported, but not recommended for sure.

[meno]

I understand I know it is not recommended,
but I would like to know reason for this.
Performance degradation in case of interrupted replication or something else?

[Torsten.]

I can't remember where it is written, but this logging keeps the FATA drives much too busy.

[Sivaramakrishna_1]

Hi,

Actually DR logs will not use in synchronous replication. These will be used only in Asynchronous mode only. Generally FATA DG will not prefer for DR Group logs for production environment because of the Performance and Duty Cycle of FATA Drives.

[Gerson Talla]

Out of curiosity, are you going to replicate the fatadisks to the 2nd EVA or are you just want to use fatadisks for the DR Group Logs?

[meno]

Almost all virtual disks are on FC drives, only 2 or 3 LUNs are on FATA drives.

[meno]

I want for all DR logs use FATA drives.

[Daniel_279]

The use of FATA drives on a destination array is supported with HP Continuous Access EVA. However, you must ensure that the I/O activity to the source array does not exceed the reduced duty cycle requirements for FATA drives.

Before using FATA drives in a HP Continuous Access EVA environment, the following factors must be considered :

â ¢ FATA drive duty cycleâ FATA drives have a reduced duty cycle relative to Fibre Channel drives.
â ¢ Write I/O rate on the source arrayâ Evaluate the level of write activity to the DR group.
â ¢ Type of write I/Osâ sequential or randomâ Evaluate the types of writes to the DR group.

When using FATA drives on the destination array, you must ensure that the FATA drive duty cycle will not be exceeded if a DR group failover occurs. In the event of a failover, write and read I/Os are now directed at the new source (previously the destination) DR group members. If the write rates and type of writes to the source array do not meet the reduced duty cycle requirements of the FATA drives, FATA drives should not be used for DR group destination virtual disks.

IMPORTANT:
â ¢ If your environment requires the higher performance and reliability provided by Fibre Channel drives, you may want to consider using Fibre Channel drives rather than FATA drives for the destination array
DR group. This will ensure a consistent level of operation should a failover occur.
â ¢ When using FATA drives, make sure they have the latest drive firmware installed.

[meno]

Thank you Daniel. I read it already, but my question was about DR group write history logs not about DR members. I have source and destination virtual disk on FC drives and I am using synchrouns replication + I set parameter Failsafe=enabled. Then DR write logs will never be used and therefore I intend to use FATA drives for it.

Marian