23 votes

Linux goes to swap while plenty of RAM installed

There is no problem. Even if there is still available RAM, the Linux Kernel will move memory pages which are hardly ever used into swap space. It’s good to swap out memory pages that have been ...
  • 2,970
21 votes

Why should iscsi traffic be isolated?

Because: Very, very bad things will happen if someone gains unauthorized access to your storage network Very, very bad things will happen if you have your iSCSI traffic not separated, and someone ...
  • 19.5k
15 votes
Accepted

iSCSI, multiple initiators for the same LUN

You need to have some sort of either a clustered file system or distributed lock manager to avoid metadata damage done to your file system with concurrent writes. There's a good summary of this ...
12 votes
Accepted

Can you connect a SAN directly to a HBA with Fibre Channel?

You can use multipath FC connections from your servers to the MSA2040 without the use of a switch. You would connect your HBAs on thee servers to each of the two controllers on the MSA. The MSA2040 ...
  • 195k
12 votes

How to get free space from mounted drive Redhat 7

I try to do the same thing couple week ago and I don't find how to. I share the official statement on the Redhat support portal. It is currently not possible to reduce the size of a partition or ...
  • 121
12 votes
Accepted

How to get free space from mounted drive Redhat 7

Being able to run fstrim on the / partitions would be the best solution however with they way your ESXi is configured it would not be possible. You need to be able to enable discards on both the VM ...
10 votes

"Mandatory" free space on a SAN?

From what you describe, the main problem is that they decided to use a RAID5 for such a large array, which is quite a bad choice for this setup, for exactly the reason you experience: Having a 2nd ...
  • 97.2k
9 votes

Mixing HBAs in a failover cluster?

You don't really mention enough detail at all but I'd have zero concerns about mixing Emulex and QLogic - in fact in our highest-availability systems I consciously do this kind of thing, even with ...
  • 100k
9 votes
Accepted

Using non-certified hard drives in Dell MD3220 storage array

I found a tutorial. Please read Flash Dell Firmware into Seagate Generic Drives. The procedure should be the same for your Toshiba drive as the same tools are used. Dell download page: Toshiba SAS ...
  • 1,999
9 votes
Accepted

Can I dynamically expose an entire SCSI host over Fibre Channel, preferably in Linux

Sure you can do that. Good summary is here: https://forum.level1techs.com/t/fedora-diy-fc-san/122877 Some good play with SCST instead of a default LIO is here (uses QLogic HBAs): http://scst....
8 votes

I want a file search like 'Everything' for network shares

Actually, Everything Search can search on the network, but you have to create a file list yourself. Go to Tools -> File List Editor Click Edit -> Add folder --> here, select a shared folder on the ...
  • 181
8 votes
Accepted

With 200TB of needed storage, is a SAN a good idea?

If you can afford it, a centralized storage system is ideal for safely and reliably serving your company's data. That said, check your math- while it's fine to back servers and computers up to a NAS,...
  • 8,811
8 votes
Accepted

Mounting Single San Drive on Multiple Hosts

STOP WHAT YOU'RE DOING RIGHT NOW! Sorry to be so dramatic but you have a big issue here - what you're trying to do is actually very straightforward, just not using LVM. The reason is that most ...
  • 100k
8 votes
Accepted

EMC ScaleIO vs Starwind Virtual SAN

There's no good or bad here: both ref'd solutions are just very different in the way how they scale out, how they distribute data among cluster nodes and how they handle component failures. 1) Wide ...
8 votes

What differences are between a NAS, a shared disk file system on a SAN, and a distributed filesystem?

Nowadays the border between NAS and SAN is unclear especially for SMB products. Historically NAS devices consist of the bunch of disks arranged in some RAID to maximize the overall performance and ...
  • 8,723
7 votes

With 200TB of needed storage, is a SAN a good idea?

For 200TB, yes you want an array. However you're thinking in the wrong direction if you're trying to square off SAN vs. NAS. They're different tools for different jobs. NAS is network accessible - ...
  • 3,697
7 votes

Migrating from AWS EBS to Co-Lo hosted SAN/NAS

SAN/NAS for < $3,600 per TB? This is totally doable. However, don't forget that apart from SAN hardware/software itself, there are lots of things that should be considered, such as: redundant ...
  • 4,817
7 votes
Accepted

Nano Server attached to SAN doesn't see new files

NTFS is not a cluster-aware file system. It was never designed to support simultaneous access from different clients. In order to allow multiple access: configure MPIO, deploy the Failover Cluster ...
  • 4,817
7 votes
Accepted

Mapping SAN to cluster nodes

Oh god, you've not have you? You've just caused immediate, irretrievable data loss sorry. NTFS isn't a cluster-aware file system, you need something to act as a lock manager too. MS Cluster Services ...
  • 100k
7 votes

How to configure StarWind Virtual SAN Free

First off, get rid of NIC teams for your storage and synchronization networks. ISCSI networks leverage MPIO, there is no need for trunking, teaming, bonding, etc. Also, don't forget to enable MPIO in ...
  • 5,626
7 votes
Accepted

PAGE_FAULT_IN_NONPAGED_AREA when booting Windows 10 from iSCSI network drive

This appears to happen when the system page file is located on the iSCSI device. While locating the page file on iSCSI worked fine under Windows 7, it appears to be broken in Windows 10. Unfortunately,...
7 votes

Boot Windows from SAN

Booting from SAN is pretty rare these days. The hypervisors I tend to see are booted from SD cards. You can then have 100% of your local storage for VMs, or use the SAN exclusively for VMs. It's also ...
7 votes
Accepted

"Bad message" with a new SAN using multipath and iSCSI

That is normal behavior for a non-clustered file system. To use iSCSI SAN with Ubuntu compute servers, a clustered file system should be used. You should probably learn more about GPFS, GFS2, Lustre, ...
  • 1,476
7 votes

How does SAN provides block access to data?

Block access in SAN means, that VM (or hypervisor) have raw access to storage over network without any file system. It looks like raw local attached storage (DAS). Depending on SAN configuration the ...
  • 8,723
6 votes
Accepted

Limiting - IOPS in VMware causing servers to run VERY slow

I think this is doing exactly what you're asking it to. You're throttling the I/O capabilities and profile of your VMs, causing them to perform poorly. Don't do this. Micromanaging resources at the ...
  • 195k
6 votes
Accepted

Array free space requirement

Yes, it's still the convention, and yes, it holds true even as you scale. With ZFS, in fact, you really don't want to get to the 75% mark in your zpool too often. Fragmentation, snapshots and general ...
  • 195k
6 votes

Why should iscsi traffic be isolated?

Because not doing so allows regular traffic to impact on storage traffic, which is a bad idea as it means that say a user's download could delay an important read or write.
  • 100k
6 votes

SAN with a few SSD drives, or lots of old fashioned HDDs?

The rule of thumb I use for disk IO is: 75 IOPs per spindle for SATA. 150 IOPs per spindle for FC/SAS 1500 IOPs per spindle for SSD. As well as IOPs per array also consider IOPs per terabyte. It's ...
  • 3,697
6 votes
Accepted

How do I connect a disk array?

This particular "shelf" is an SAS (Serial Attached SCSI) drive array. SAS is like the SATA connection used in consumer computers for connecting hard drives, but more robust. Once of the things that it ...
  • 22.8k
6 votes
Accepted

Fiber Channel (8 Gb) or iSCSI 10 Gb

iSCSI will be fine here, especially since you already have so much of the infrastructure for it. While fiber would be less susceptible to interference, a 2Gb/s difference is enough to make up for that ...
  • 7,016

Only top scored, non community-wiki answers of a minimum length are eligible