Mirroring Bootdisks?

[sftx]

Quick question:

What is recommended if I am creating a backup server (Veritas) under Solaris 9 as far as disk configuration? I have a Sun V440 w/ (4) 72Gb drives. I need the space of 3 disks for data.

Backup disk? Hotspare?

Also would you recommend the Solaris Volume Manager or the Veritas VxVM to do this?

Thank you,
Steve

 

[cgswong]

Let me see if I understand you:

V440 backup server
- four 72 GB disks
- 3 out of 4 disks needed for storage of backup data

You can't RAID 1 a boot disk as you'd need an entire disk the same size as the OS disk. However, you can mirror slices from one disk to another (on the same physical disk wouldn't make sense). This way you can still use the remainder of the disks for data.

As far as I know you can't have a hotspare for the OS disk unless it's already in a redundant setup (RAID 1,3,5,10) as the disk would have had to fail for the spare to start being populated in which case your server would probably be offline if the OS disk failed.

You could also backup the OS slices to tape every week or so depending on how frequently things change or your backup policy dictates. Of course would have downtime restoring from tape.

I think the choice of SVM or VVM for simple OS mirroring is a matter of preference in the end but it's best to have a single volume manager running so whichever one you choose use that for the OS disk mirroring as well.

For me, I prefer to have a single mount point for all OS files (i.e. '/') as it keeps things simple. I also prefer to mirror the OS disk as this negates any downtime of swapping in a backup disk or restoring from tape.

Hope this helps.



The ONE ( HP-UX + Solaris + AIX + Tru64 = Unix)

 

[daFranze]

if you do not have a Veritas Volume Manager license use Solaris Volume Manager (aka. Solstice DiskSuite); I prefere SVM since it is easy to handle with a smart and small CLI;

depending on the layout of your root disk I recommend something like this (I prefere to install everything in one slice! This is my personal taste! )

...s0 is / with 4-5 Gigs
...s1 is swap (rule of thumb is 2xRAM)
...s3 is your data
...s7 is your metadb with about 30-40 MBytes

after OS Installation copy the layout to all disks (you can use format or prtvtoc + fmthard) and create replicates of the metadbs and configure a RAID5 volume over 4 ...s3 Disks; mirror "/" and "swap", in this configuration you can create a 3 way mirror of both Filesystems and hotspare the 4th disk...

btw: a SOFT-RAID5 is usually very slow (rule of thumb: about 70% performance of a single disk!)

waht you need is 6 disks for a mirror!

Regards
-- Franz
Sorry I'm not a native spaeker, I'm from Munich, Germany - "Home of the Whopper", oh no, "Home of the Oktoberfest" ;-)
Solaris System Manager; I used to work for Sun Microsystems Support (EMEA) for 5 years

 

[sftx]

Franz:

Ok, I am slowly getting up to speed on this.

Looks like I have to go with SVM...
From what I understand (which isn't a whole lot at this point) , Since I have 8GB of Ram, I don't need the traditional 2xRam. What are your thoughts. Sun said about 1-2GB should be OK. All this box will be running is Veritas Netbackup Software and nothing else.

A few questions for you on what you had mentioned:

"after OS Installation copy the layout to all disks (you can use format or prtvtoc + fmthard)"
----layout being the sizes of the slices, right?! and copy being just reproduce the exact same sizes manually?

"and create replicates of the metadbs"
----aren't metadbs only created once you use SVM?

"and configure a RAID5 volume over 4 ...s3 Disks; mirror "/" and "swap", in this configuration you can create a 3 way mirror of both Filesystems and hotspare the 4th disk..."
----could you elaborate on this one for me a bit more. You mentioned a Raid5 over 4 ...s3 disks, but then you mention the 4th disk being the hotspare.

Mirror "/" & "swap" on 3 disks?

Wish I could do the 6 disk mirror, but only have 4 slots at this point to work with.

Any extra information would be great. This sounds like a great idea.

Thanks,
SteveF

 

[daFranze]

since you have 8GB RAM you can run the machine even without any swapspace; you can add a swapfile if you need one later (mkfile size filename; swap -a filename)

layout: yes, the size of the slices; you can do this with format, eg:
----------------------------------------------------------
# format
Searching for disks...done


AVAILABLE DISK SELECTIONS:
0. c1t0d0 <SUN18G cyl 7506 alt 2 hd 19 sec 248>
/pci@8,600000/SUNW,qlc@4/fp@0,0/ssd@w210000203738238d,0
1. c1t1d0 <SUN18G cyl 7506 alt 2 hd 19 sec 248>
/pci@8,600000/SUNW,qlc@4/fp@0,0/ssd@w210000203738237f,0
Specify disk (enter its number): 0
selecting c1t0d0
[disk formatted]


FORMAT MENU:
disk - select a disk
type - select (define) a disk type
partition - select (define) a partition table
current - describe the current disk
format - format and analyze the disk
repair - repair a defective sector
label - write label to the disk
analyze - surface analysis
defect - defect list management
backup - search for backup labels
verify - read and display labels
save - save new disk/partition definitions
inquiry - show vendor, product and revision
volname - set 8-character volume name
!<cmd> - execute <cmd>, then return
quit
format> p


PARTITION MENU:
0 - change `0' partition
1 - change `1' partition
2 - change `2' partition
3 - change `3' partition
4 - change `4' partition
5 - change `5' partition
6 - change `6' partition
7 - change `7' partition
select - select a predefined table
modify - modify a predefined partition table
name - name the current table
print - display the current table
label - write partition map and label to the disk
!<cmd> - execute <cmd>, then return
quit
partition> name
Enter table name (remember quotes): Steve

partition> q


FORMAT MENU:
disk - select a disk
type - select (define) a disk type
partition - select (define) a partition table
current - describe the current disk
format - format and analyze the disk
repair - repair a defective sector
label - write label to the disk
analyze - surface analysis
defect - defect list management
backup - search for backup labels
verify - read and display labels
save - save new disk/partition definitions
inquiry - show vendor, product and revision
volname - set 8-character volume name
!<cmd> - execute <cmd>, then return
quit
format> dis


AVAILABLE DISK SELECTIONS:
0. c1t0d0 <SUN18G cyl 7506 alt 2 hd 19 sec 248>
/pci@8,600000/SUNW,qlc@4/fp@0,0/ssd@w210000203738238d,0
1. c1t1d0 <SUN18G cyl 7506 alt 2 hd 19 sec 248>
/pci@8,600000/SUNW,qlc@4/fp@0,0/ssd@w210000203738237f,0
Specify disk (enter its number)[0]: 1
selecting c1t1d0
[disk formatted]
format> p


PARTITION MENU:
0 - change `0' partition
1 - change `1' partition
2 - change `2' partition
3 - change `3' partition
4 - change `4' partition
5 - change `5' partition
6 - change `6' partition
7 - change `7' partition
select - select a predefined table
modify - modify a predefined partition table
name - name the current table
print - display the current table
label - write partition map and label to the disk
!<cmd> - execute <cmd>, then return
quit
partition> sel
0. Steve
Specify table (enter its number)[0]:
----------------------------------------------------------

or use
prtvtoc and fmthard: if your disks are c0t0d0, c0t1d0, c1t0d0 and c1t1d0

check the layout of the masterdisk (s0 is / ~~5Gig, s1 is the datablock ~~65Gigs, s7 for metadb ~~30MB)

prtvtoc /dev/rdsk/c0t0d0s2 | fmthard -s - /dev/rdsk/c0t1d0s2
prtvtoc /dev/rdsk/c0t0d0s2 | fmthard -s - /dev/rdsk/c1t0d0s2
prtvtoc /dev/rdsk/c0t0d0s2 | fmthard -s - /dev/rdsk/c1t1d0s2

----aren't metadbs only created once you use SVM?
as a first step you would create a metadb on your boot disk (slice 7 in my example) and add some metadbs later on other disks


"and configure a RAID5 volume over 4 ...s3 Disks; mirror "/" and "swap", in this configuration you can create a 3 way mirror of both Filesystems and hotspare the 4th disk..."
----could you elaborate on this one for me a bit more. You mentioned a Raid5 over 4 ...s3 disks, but then you mention the 4th disk being the hotspare.
Mirror "/" & "swap" on 3 disks?

yes, I suggest to RAID5 the data area and create a three way mirror for root (and swap if you decide to habe swapspace); then you have the 4th disk unused in Slice 0, you can use this as a hotspare slice.

If you need more info just add another post...
Do you need info about HOWTO create SDS/SVM Metadevices?




Regards
-- Franz
Sorry I'm not a native spaeker, I'm from Munich, Germany - &quot;Home of the Whopper&quot;, oh no, &quot;Home of the Oktoberfest&quot; ;-)
Solaris System Manager; I used to work for Sun Microsystems Support (EMEA) for 5 years

 

[daFranze]

edit: on my Sol9 with SVM 4.2.1 s7 is just 6 cylinders (36 Gig disks this is 16MB) large

in Germany we celebrate Easter, so I'm back on tuesday April 13th...

Regards
-- Franz
Sorry I'm not a native spaeker, I'm from Munich, Germany - &quot;Home of the Whopper&quot;, oh no, &quot;Home of the Oktoberfest&quot; ;-)
Solaris System Manager; I used to work for Sun Microsystems Support (EMEA) for 5 years