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Questions tagged [lun]

90 questions
27
votes
7 answers

SQL Server disk design on an ISCSI SAN

Its standard practice to separate log and data files to separate disks away from the OS (tempdb, backups and swap file also) Does this logic still make sense when your drives are all SAN based and your LUNS are not carved of specific disk or raid…
CPU_BUSY
  • 2,342
13
votes
4 answers

What is the difference between LVM and LUN

Both seem to be a virtualization layer on top of physical disks. I'm having a hard-time understanding each of them and the difference between them.
BlueGene
  • 2,241
6
votes
5 answers

LUNs and virtual machines

I have HP P2000 + XenServer solution working. What I'm thinking about is how to create LUNs for 20 virtual machines. Separate LUN for every VM ? It gives me ability to backup the specific virtual machine, however 20 vm = 20 shared storages in…
John
  • 1,493
4
votes
2 answers

iSCSI: LUNs per target?

My question relates specifically to ZFS/COMSTAR but I assume is generally applicable to any iSCSI system. Should one prefer to create a target for every LUN that you want to expose? Or is it good practise to have a single target with multiple…
badnews
  • 615
4
votes
1 answer

SAN: is it better to have separate LUNs for operating system and data of virtual machines?

We have an iSCSI SAN that will be used as backing store for virtual machines. We use Xen and will directly present the LUNs as block devices of VMs (so there is no file system with files on it for each VM, like VMware does when using VMFS…
Luke404
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  • 59
4
votes
1 answer

Considerations for spanned volumes with SAN's LUN.

I want to know, before going forward, what I can expected in lost of performance (or not) of creating Windows spanned volumes from LUN delivered by a SAN ? I don't know which kind of SAN is (we don't administer it), but they give us 10 300 Gb LUN to…
Patrick Pellegrino
  • 133
4
votes
2 answers

LUN and VMFS 5 sizing assistance

I am working on setting up our vSphere 5 environment. With vSphere 5 you can go > the 2TB VMFS datastore size that you were capped at with in 4.x, etc. What size datastores are people using and whats a good way to determine the correct size? My…
Chadddada
  • 1,710
3
votes
1 answer

ISCSI target service on Centos OS 7 errors

I have problem with ISCSI Target Utils. Service started normally, but showing errors: systemd[1]: Starting tgtd iSCSI target daemon... tgtd[3138]: tgtd: iser_ib_init(3436) Failed to initialize RDMA; load kernel modules? tgtd[3138]: tgtd:…
eurotornado
  • 31
3
votes
1 answer

Unable to mount xfs volume to replay log. Now what?

42TB LUN, formatted in XFS and shared via NFS was reported 'unavailable' by customers. In the end I was forced to restart the file server. The XFS LUN won't mount until it is repaired, and to repair I need to mount it so the log will replay and…
Jeter-work
  • 870
3
votes
3 answers

What are your recommendations/best-practices for vDisk/datastore/LUN management with VMWare ESX

Obviously there's an infinite variety of ways of carving up your raw SAN LUNs to provide VM boot and data vDisks - but what methods do you use, what are their pros/cons, and are there any good 'best-practice' docs you've come across (other then the…
Chopper3
  • 101,808
3
votes
4 answers

No LUN available to extend datastore

I have a HP DL380G5 with ESXi 5.5 and x4 146GB Sata disks in a RAID5 array. I have added one more disk to the server exactly as the other ones and, using SmartStart CD I managed to add the disk to the array. No issues so far. Next day, using the…
gasfe78
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3
votes
2 answers

Multiple iSCSI LUNs to one Server

I'm reasonably sure i'm ok to do this, but I would love some confirmation. Simple question, can I have two LUNs from the same SAN attached to the same server? More detail: I have a HP MSA2000 SAN, connecting to multiple Win 2008 R2 servers over…
donrosco
  • 130
3
votes
2 answers

How do you remove attached FC LUNS from CentOS 6?

We have a Qlogic QLE2560 HBA running on a Centos 6 server. I am needing to remove the attached LUNS remotely. I do not have any software from qlogic installed on the device. Their are 2 LUNS attached to a P200 G3 SAN and I can not find anything…
Justin S
  • 350
3
votes
1 answer

ESXi 4.1: how to make use of an iSCSI LUN bigger than 2 TB?

I have a ESXi servers (4.1 U1) connected to an iSCSI NAS, where 4 LUNS have been defined and presented to this host; all the LUNs are 3 TB in size. ESXi correctly sees the LUNs and acknowledges their 3 TB size. I know the maximum size for a VMFS…
Massimo
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3
votes
2 answers

The Linux SCSI layer does not automatically remap LUN assignments

I've got some iSCSI/FC storage, currently using only iSCSI. I have in general no problems with mounting LUNs - under Linux and under Windows. Unfortunately - when I add LUN for my Linux iSCSI initiator - I receive info in messages: Warning!…
Arek B.
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