How can I tell what level of RAID I am running?

[Mott Given]

We are using an EMC Symmetrix model 3700 device on one of our hosts. How can I tell what level of RAID our system is using (eg. RAID 1, RAID 5, etc.)?

ALso, how can I tell what the "DM-NUM" and "DISK-SIZE" values are for this machine?. These parameters are used by our Patrol (Best/1) software. The "DM-NUM" is the number of physical disk modules associated with the RAID device

Mott Given, mgiven@dsdc.dla.mil.

[Rita C Workman]

Here's something you could read on RAID that may help you answer your question:

http://docs.hp.com/hpux/onlinedocs/J6173-90002/J6173-90002.html

[Kofi ARTHIABAH]

EMC disk arrays are managed with a software called Navisphere. There is a Windows 95 supervisor which you can run to query the array for configuration - that should tell you what you have in terms of RAID1 RAID5 etc.

your second question: you need to use the diskinfo -v command (after running ioscan -fnC disk to find out the disk device names.)

[Deshpande Prashant]

Hi
We are using here EMC3930 box with HP N4000 machines.
I use EMC symmmetrics (new version is controle center) software. It has a utility "inq" which gives details of EMC lun nos. and related hp device files and disk size.
The raid configuration on EMC is internal to box and not seen by HP machine. EMC hardware eng. will be able to give you information about raid information in EMC boxes.

Hope it helps.
Thanks.
Prashant Deshpande.

[JC Hoffecker · Accepted solution]

The EMC Symmetrix runs RAID-1 and RAID-S. Both are done totally by the Symmetrix microcode. RAID-1 is disk mirroring, RAID-S is basically RAID-5 (3+1). You can have both in your Symmetrix at the same timeas the protection type (RAID-1 or RAID-S) is done on a logical volume (LUN) level. You can also have two Symmetrix connected together in which case you have disk mirroring but it is across two boxes. This is called SRDF. With SRDF, the first mirror is one Symmetrix and second mirror is in another Symmetrix. Local disk mirroring may be combined with SRDF to provide both local and remote protection. With the Symmetrix you should not use host mirroring or host raid-5 via the LVM. This just adds unnecessary overhead on the server.

Be glad you've got a Symmetrix as it brings lots of funcationality along with it, such as Powerpath, Timefinder, ECC, etc.

Many shops use raid-1 for database logs and raid-s for the tables as all the raid-5 types have a penality associated with doing a lot of write activity.

To determine your exact configuration on a volume by volume basis, ask your support engineer or your System Engineer for a Symmwinn map of your Symmetrix. If you have the ECC (Enterprise Control Center) package, EMC will install it for you and it will easily tell you which volumes have raid-1 or raid-s protection. It will also show you a tremendous amount of performance information about what the disks are doing, allow you to reconfigure the disks with a mouse and much more.

Running the inq command will show you the disk volumes but I don't think it will show you the protection type.

[liam Fogarty_1]

download the INQ exe from emc.com.
once run this will show you what type of protection/raid you are running
> inq -et
This will return with your protection e.g. mirrored (raid1), RDF1+mirrored (raid1 with remote replication)

Alternativley if you have symcli
then do a
> symdev list
this will the protection as 2-way-mirr, again this is raid 1.

hope this helps...
Liam

[Stuart Abramson_2]

Liam has the right answer, again:

# inq -et -nodots

Inquiry utility, Version V7.3-173 (Rev 1.1) (SIL Version V4.3.1.1 (Edit Level 173)
Copyright (C) by EMC Corporation, all rights reserved.
For help type inq -h.


---------------------------------------------------------------------------------------------------------------
RAW SERIAL BCV/ R1/ CKD/ FIBRE/ SHARE/ SYMM DEVICE UDATE
DEVICE NAME NUMBER REG? R2? FBA? ULTRA? META MODEL PROTECTION WD? DIR-P (YYYYMMDD)
---------------------------------------------------------------------------------------------------------------
/dev/rdsk/c12t0d0 :21000000 :REG :N/A :FBA :FIBRE :S :SYMM5 :mirrored :WP :R14A-0 :20030502
/dev/rdsk/c12t0d1 :21001000 :REG :N/A :FBA :FIBRE :S :SYMM5 :mirrored : :R14A-0 :20030502
/dev/rdsk/c12t0d2 :21002000 :REG :N/A :FBA :FIBRE :S :SYMM5 :mirrored : :R14A-0 :20030502
/dev/rdsk/c12t0d3 :21003000 :REG :N/A :FBA :FIBRE :S :SYMM5 :mirrored : :R14A-0 :20030502

[Alzhy]

LUNs (or "disks") coming out of the biggies -- EMC, HDS/HP (XP Series), IBM Shark, Sun -- will always come out as RAID protected already (either 10/01 - mirror/stripes, RAID5 (parity) or some proprietary RAIDing scheme..). As the others have mentioned -- for EMC -- there is that ever famous and handy "inq" utility. For most RAID arrays -- ask your Storage Admin if you do not wear the same hat.

Bear in mind also that aside from Array based RAID implementations - you will also find software RAID implementations. For very large and highly available environments, software RAID (via LVM or VxVM) is further used to enhance performance and further increase redundancy. A colleauge of mine working in the Genome industry builds volumes/filesystems that are software striped/mirrored/RAID5 of entire arrays -- ie. accross separate HDS9900's on different HBA's. For some of my volumes -- to totally avoid points of failure, I usually mirror/stripe or RAID5 already "RAIDed" LUNS... so a LUN failure or a Cable/HBA break wil not bring my storage down...