Linux – How to check if server really has RAID 10 enabled

centos6linuxraidraid10

I have a dedicated server with 4 hdd and RAID 10, with Cent OS 6.4

How can I check if RAID is really enabled. I'm in doubt because on another server with RAID 10 enabled, I can see in /dev sg0 sg1 sg2 sg3 sg4, and with the command smartctl -d scsi –all /dev/sga1 for example, I can get info about the disks.

In this new server, I don't have this.

Is there any other way to check if it really have RAID enabled?

Best Answer

You will need to determine your RAID controller. This could be any number of hardware RAID cards or software RAID.

Once the RAID controller is identified, you can then download and install the appropriate RAID utilities to check RAID status.

I have found many hosting providers do not actually monitor RAID status. So it is good to check yourself and configure alerts if possible.

Either ask the company what RAID controller is in use or you can use a tool like lspci or lshw (available in the EPEL) to list hardware.

I often use lshw to confirm the hardware I've ordered form a IaaS provider is indeed what it is supposed to be.

lshw man page: http://linux.die.net/man/1/lshw

Related Solutions

Linux – Software Raid 10 corrupted superblock after dual disk failure, how to recover it

As the owner of professional data recovery firm the proper way to rebuild a broken RAID like this would be to create clones or images of each drive. Never work with the originals. Once you have images of the drives you would need to recreate the RAID in some kind of software like X-Ways. Be sure to keep the correct order of the drives! It can be quite complicated rebuilding RAID ARRAYS, and if the data is important you should label the drives and send them out to a reputable company, but most RAID recoveries are not cheap.

How to create Raid 10 with megacli

Response a Create Raid 10 (not Raid 6)

First get the Adapter #
```
# MegaCli Adpallinfo -aall | grep '^Adapter'  
Adapter #0   
```
MegaCli or megacli depending distro *nix

In this case Adapter it's Adapter #0

Get Device ID and Slot disk values:

 # MegaCli64 -PDlist -aall | grep -e '^Enclosure Device ID:' -e '^Slot Number:'
 Enclosure Device ID: 252
 Slot Number: 0
 Enclosure Device ID: 252
 Slot Number: 1
 Enclosure Device ID: 252
 Slot Number: 2
 Enclosure Device ID: 252
 Slot Number: 3

ID in this case for all it's 252

According MegaCli command for create RAID 10 it's MegaCli -CfgSpanAdd -r10 -Array0[E:S,E:S] -Array1[E:S,E:S] -aN
```
MegaCli -CfgSpanAdd -R10 -Array0[252:0,252:2] -Array1[252:1,252:3] -a0
```
In this case, create a RAID 10, creating one array for Raid1 with disk 0 and 2, and other array for Raid1 with disks 1 and 3 and N = 0 (-a0)

Verify RAID

 # megasasctl
 a0       LSI MegaRAID SAS 9271-4i encl:1 ldrv:1  batt:FAULT, low voltage, charge failed
 a0d0      1489GiB RAID 10  2x2  optimal
 a0e252s0    745GiB  a0d0  online
 a0e252s1    745GiB  a0d0  online
 a0e252s2    745GiB  a0d0  online
 a0e252s3    745GiB  a0d0  online

Or if megasasctl is unavailable:

 # MegaCli -LDInfo -Lall -aALL
 Adapter 0 -- Virtual Drive Information:
 Virtual Disk: 0 (Target Id: 0)
 Name:
 RAID Level: Primary-1, Secondary-0, RAID Level Qualifier-0
 Size:1.454 TB
 State: Optimal
 Stripe Size: 256 KB
 Number Of Drives per span:2
 Span Depth:2
 Default Cache Policy: WriteBack, ReadAhead, Direct, No Write Cache if Bad BBU
 Current Cache Policy: WriteBack, ReadAhead, Direct, No Write Cache if Bad BBU
 Access Policy: Read/Write
 Disk Cache Policy: Enabled
 Encryption Type: None

Best Answer

Related Solutions

Linux – Software Raid 10 corrupted superblock after dual disk failure, how to recover it

How to create Raid 10 with megacli

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