Posts Tagged ‘nexentastor’


Quick-Take: NexentaStor 3.1.3 New AD Group Feature, Can Break AD Shares

June 12, 2012

The latest update of NexentaStor may not go too smoothly if you are using Windows Server 2008 AD servers and delegating shares via NexentaStor. While the latest update includes a long sought after fix in AD capabilities (see pull quote below) it may require a tweak to the CIFS Server settings to get things back on track.

Domain Group Support

It is now possible to allow Domain groups as members of local groups. When a Windows client authenticates with NexentaStor using a domain account, NexentaStor consults the domain controller for information about that user’s membership in domain groups. NexentaStor also computes group memberships based on its _local_ groups database, adding both local and domain groups based on local group memberships, which are allowed to be indirect. NexentaStor’s computation of group memberships previously did not correctly handle domain groups as members of local groups.

NexentaStor 3.1.3 Release Notes

In the past, some of NexentaStor’s in-place upgrades have reset the “lmauth_level” of the associated SMB share server from its user configured value back to a “default” of four (4). This did not work very well in an AD environment where the servers were Windows Server 2008 and running their native authentication mode. The fix was to change the “lmauth_level” to two (2) via the NMV or NMC (“sharectl set -p lmauth_level=2 smb”) and restart the service. If you have this issue, the giveaway kernel log entries are as follows:

smbd[7501]: [ID 702911 daemon.notice] smbd_dc_update: myad.local: locate failed
smbd[7501]: [ID 702911 daemon.notice] smbd_dc_monitor: domain service not responding

However, the rules have changed in some applications; Nexenta’s new guidance is:

Summary Description CIFS Issue

A recent patch release by Microsoft has necessitated a changed to the CIFS authorization setting. Without changing this setting, customers will see CIFS disconnects or the appliance being unable to join the Active Directory domain. If you experience CIFS disconnects or problems joining your Active Directory domain, please modify the ‘lmauth_level’ setting.

# sharectl set -p lmauth_level=4 smb

– NexentaStor 3.1.3 Release Notes

While this may work for others out there it does not universally work for any of my tested Windows Server 2008 R2, native AD mode servers. Worse, it appears to work with some shares, but not all; this can lead to some confusion about the actual cause (or resolution) of the problem based on the Nexenta release notes. Fortunately (or not, depending on your perspective), the genesis of NexentaStor is clearlyheading toward an intersection with Illumos although the current kernel is still based on Open Solaris (134f), and a post from OpenIndiana points users to the right solution.

(Jonathan Leafty) I always thought it was weird that lmauth_level had to be set to 2 so I
bumped it back to the default of 3 and restarted smb and it worked...
(Gordon Ross) Glad you found that.  I probably should have sent a "heads-up" when the
"extended security outbound" enhancement went in.  People who have
adjusted down lmauth_level should put it back the the default.

– CIFS in Domain Mode (AD 2008), OpenIndiana Discussion Group (

Following the advice for OpenIndiana re-enabled all previously configured shares. This mode is also the default for Solaris, although NexentaStor continues to use a different one. According to the man pages for smb on Nexenta (‘man smb(4)’) the difference between ‘lmauth_level=3’ and ‘lmauth_level=4’ is as follows:


Specifies the LAN Manager (LM) authentication level. The LM compatibility level controls the type of user authentication to use in workgroup mode or
domain mode. The default value is 3.

The following describes the behavior at each level.

2 – In Windows workgroup mode, the Solaris CIFS server accepts LM, NTLM, LMv2, and NTLMv2 requests. In domain mode, the SMB redirector on
the Solaris CIFS server sends NTLM requests.

3 – In Windows workgroup mode, the Solaris CIFS server accepts LM, NTLM, LMv2, and NTLMv2 requests. In domain mode, the SMB redirector on
the Solaris CIFS server sends LMv2 and NTLMv2 requests.

4 – In Windows workgroup mode, the Solaris CIFS server accepts NTLM, LMv2, and NTLMv2 requests. In domain mode, the SMB redirector on the
Solaris CIFS server sends LMv2 and NTLMv2 requests.

5 – In Windows workgroup mode, the Solaris CIFS server accepts LMv2 and NTLMv2 requests. In domain mode, the SMB redirector on the Solaris
CIFS server sends LMv2 and NTLMv2 requests.

Manpage for SMB(4)

This illustrates either a continued dependency on LAN Manager (absent in ‘lmauth_level=4’) or a bug as indicated in the OpenIndiana thread. Either way, more testing to determine if this issue is unique to my particular 2008 AD environment or this is a general issue with the current smb/server facility in NexentaStor…

SOLORI’s Take: So while NexentaStor defaults back to ‘lmauth_level=4’ and ‘lmauth_level=2’ is now broken (for my environment), the “default” for OpenIndiana and Solaris (‘lmauth_level=3’) is a winner; as to why – that’s a follow-up question… Meanwhile, proceed with caution when upgrading to NexentaStor 3.1.3 if your appliance is integrated into AD – testing with the latest virtual appliance for the win.


In-the-Lab: NexentaStor vs ESXi, Redux

February 24, 2012

In my last post, I mentioned a much complained about “idle” CPU utilization quirk with NexentaStor when running as a virtual machine. After reading many supposed remedies on forum postings (some reference in the last blog, none worked) I went pit-bull on the problem… and got lucky.

As an avid (er, frequent) NexentaStor user, the luster of the NMV (Nexenta’s Web GUI) has worn off. Nearly 100% of my day-to-day operations are on the command line and/or Nexenta’s CLI (dubbed NMC). This process includes power-off events (from NMC, issue “setup appliance power-off” or “setup appliance reboot”).

For me, the problem cropped-up while running storage benchmarks on some virtual storage appliances for a client. These VSA’s are bound to a dedicated LSI 9211-8i SAS/6G controller using VMware’s PCI pass-through (Host Configuration, Hardware, Advanced Settings). The VSA uses the LSI controller to access SAS/6G disks and SSDs in a connected JBOD – this approach allows for many permutations on storage HA and avoids physical RDMs and VMDKs. Using a JBOD allows for attachments to PCIe-equipped blades, dense rack servers, etc. and has little impact on VM CPU utilization (in theory).

So I was very surprised to find idle CPU utilization (according to ESXi’s performance charting) hovering around 50% from a fresh installation. This runs contrary to my experience with NexentaStor, but I’ve seen reports of such issues on the forums and even on my own blog. I’ve never been able to reproduce more than a 15-20% per vCPU bias between what’s reported in the VM and what ESXi/vCenter sees. I’ve always attributed this difference to vSMP and virtual hardware (disk activity) which is not seen by the OS but is handled by the VMM.

CPU record of idle and IOzone testing of SAS-attached VSA

During the testing phase, I’m primarily looking at the disk throughput, but I notice a persistent CPU utilization of 50% – even when idle. Regardless, the 4 vCPU VSA appears to perform well (about 725MB/sec 2-process throughput on initial write) despite the CPU deficit (3 vCPU test pictured above, about 600MB/sec write). However, after writing my last blog entry, the 50% CPU leach just kept bothering me.

After wasting several hours researching and tweaking with very little (positive) effect, a client e-mail prompted a NMV walk through with resulted in an unexpected consequence: the act of powering-off the VSA from web GUI (NMV) resulted is significantly reduced idle CPU utilization.

Getting lucky: noticing a trend after using NMV to reboot for a client walk-through of the GUI.

Working with the 3 vCPU VSA over the previous several hours, I had consistently used the NMC (CLI) to reboot and power-off the VM. The fact of simply using the NMV to shutdown the VSA couldn’t have anything to do with idle CPU consumption, could it? Remembering that these were fresh installations I wondered if this was specific to a fresh installation or could it show up in an upgrade. According to the forums, this only hampered VMs, not hardware.

I grabbed a NexentaStor 3.1.0 VM out of the library (one that had been progressively upgraded from 3.0.1) and set about the upgrade process. The result was unexpected: no difference in idle CPU from the previous version; this problem was NOT specific to 3.1.2, but specific to the installation/setup process itself (at least that was the prevailing hypothesis.)

Regression into my legacy VSA library, upgrading from 3.1.1 to 3.1.2 to check if the problem follows the NexentaStor version.

If anything, the upgraded VSA exhibited slightly less idle CPU utilization than its previous version. Noteworthy, however, was the extremely high CPU utilization as the VSA sat waiting for a yes/no response (NMC/CLI) to the “would you like to reboot now” question at the end of the upgrade process (see chart above). Once “no” was selected, CPU dropped immediately to normal levels.

Now it seemed apparent that perhaps an vestige of the web-based setup process (completed by a series of “wizard” pages) must be lingering around (much like the yes/no CPU glutton.) Fortunately, I had another freshly installed VSA to test with – exactly configured and processed as the first one. I fired-up the NMV and shutdown the VSA…

Confirming the impact of the "fix" on a second fresh installed NexentaStor VSA

After powering-on the VM from the vSphere Client it was obvious. This VSA had been running idle for some time, so it’s idle performance baseline – established prior across several reboots from CLI – was well recorded by the ESXi host (see above.) The resulting drop in idle CPU was nothing short of astounding: the 3 vCPU configuration has dropped from a 50% average utilization to 23% idle utilization. Naturally, these findings (still anecdotal) have been forwarded on to engineers at Nexenta. Unfortunately, now I have to go back and re-run my storage benchmarks; hopefully clearing the underlying bug has reduced the needed vCPU count…


In-the-Lab: NexentaStor and VMware Tools, You Need to Tweak It…

February 24, 2012

While working on an article on complex VSA’s (i.e. a virtual storage appliance with PCIe pass-through SAS controllers) an old issue came back up again: NexentaStor virtual machines still have a problem installing VMware Tools since it branched from Open Solaris and began using Illumos. While this isn’t totally Nexenta’s fault – there is no “Nexenta” OS type in VMware to choose from – it would be nice if a dummy package was present to allow a smooth installation of VMware Tools; this is even the case with the latest NexentaStor release: 3.1.2.

I could not find where I had documented the fix in SOLORI’s blog, so here it is… Note, the NexentaStor VM is configured as an Oracle Solaris 11 (64-bit) virtual machine for the purpose of vCenter/ESXi. This establishes the VM’s relationship to a specific VMware Tools load. Installation of VMware Tools in NexentaStor is covered in detail in an earlier blog entry.

VMware Tools bombs-out at SUNWuiu8 package failure. Illumos-based NexentaStor has no such package.

Instead, we need to modify the script directly to compensate for the loss of the SUNWuiu8 package that is explicitly required in the installation script.

Commenting out the SUNWuiu8 related section allows the tools to install with no harm to the system or functionality.

Note the full “if” stanza for where the VMware Tools installer checks for ‘tools-for-solaris’ must be commented out. Since the SUNWuiu8 package does not exist – and more importantly is not needed for Illumos/Nexenta – removing a reference to it is a good thing. Now the installation can proceed as normal.

After the changes, installation completes as normal.

That’s all there is to getting the “Oracle Solaris” version of VMware Tools to work in newer NexentaStor virtual machines – now back to really fast VSA’s with JBOD-attached storage…

SOLORI’s Note: There is currently a long-standing bug that affects NexentaStor 3.1.x running as a virtual machine. Currently there is no known workaround to keep NexentaStor from running up a 50% cpu utilization from ESXi’s perspective. Inside the NexentaStor VM we see very little CPU utilization, but from the performance tab, we see 50% utilization on every configured vCPU allocated to the VM. Nexenta is reportedly looking into the cause of the problem.

I looked through this and there is nothing that stands out other that a huge number of interrupts while idle. I am not sure where those interrupts are coming from. I see something occasionally called volume-check and nmdtrace which could be causing the interrupts.

Nexenta Support

A bug report was reportedly filed a couple of days ago to investigate the issue further.


In-the-Lab: Default Rights on CIFS Shares

December 6, 2010

Following-up on the last installment of managing CIFS shares, there has been a considerable number of questions as to how to establish domain user rights on the share. From these questions it is apparent that the my explanation about root-level share permissions could have been more clear. To that end, I want to look at default shares from a Windows SBS Server 2008 R2 environment and translate those settings to a working NexentaStor CIFS share deployment.

Evaluating Default Shares

In SBS Server 2008, a number of default shares are promulgated from the SBS Server. Excluding the “hidden” shares, these include:

  • Address
  • ExchangeOAB
  • Public
  • RedirectedFolders
  • UserShares
  • Printers

Therefore, it follows that a useful exercise in rights deployment might be to recreate a couple of these shares on a NexentaStor system and detail the methodology. I have chosen the NETLOGON and SYSVOL shares as these two represent default shares common in all Windows server environments. Here are their relative permissions:


From the Windows file browser, the NETLOGON share has default permissions that look like this:

NETLOGON Share permissions

Looking at this same permission set from the command line (ICALCS.EXE), the permission look like this:

NETLOGON permissions as reported from icacls
The key to observe here is the use of Windows built-in users and NT Authority accounts. Also, it is noteworthy that some administrative privileges are different depending on inheritance. For instance, the Administrator’s rights are less than “Full” permissions on the share, however they are “Full” when inherited to sub-dirs and files, whereas SYSTEM’s permissions are “Full” in both contexts.


From the Windows file browser, the NETLOGON share has default permissions that look like this:

SYSVOL network share permissions

Looking at this same permission set from the command line (ICALCS.EXE), the permission look like this:

SYSVOL permissions from ICACLS.EXE
Note that Administrators privileges are truncated (not “Full”) with respect to the inherited rights on sub-dirs and files when compared to the NETLOGON share ACL.

Create CIFS Shares in NexentaStor

On a ZFS pool, create a new folder using the Web GUI (NMV) that will represent the SYSVOL share. This will look something like the following:
Creating the SYSVOL share
Read the rest of this entry ?


In-the-Lab: NexentaStor vs. Grub

November 16, 2010

In this In-the-Lab segment we’re going to look at how to recover from a failed ZFS version update in case you’ve become ambitious with your NexentaStor installation after the last Short-Take on ZFS/ZPOOL versions. If you used the “root shell” to make those changes, chances are your grub is failing after reboot. If so, this blog can help, but before you read on, observe this necessary disclaimer:

NexentaStor is an appliance operating system, not a general purpose one. The accepted way to manage the system volume is through the NMC shell and NMV web interface. Using a “root shell” to configure the file system(s) is unsupported and may void your support agreement(s) and/or license(s).

That said, let’s assume that you updated the syspool filesystem and zpool to the latest versions using the “root shell” instead of the NMC (i.e. following a system update where zfs and zpool warnings declare that your pool and filesystems are too old, etc.) In such a case, the resulting syspool will not be bootable until you update grub (this happens automagically when you use the NMC commands.) When this happens, you’re greeted with the following boot prompt:


Grub is now telling you that it has no idea how to boot your NexentaStor OS. Chances are there are two things that will need to happen before your system boots again:

  1. Your boot archive will need updating, pointing to the latest checkpoint;
  2. Your master boot record (MBR) will need to have grub installed again.

We’ll update both in the same recovery session to save time (this assumes you know or have a rough idea about your intended boot checkpoint – it is usually the highest numbered rootfs-nmu-NNN checkpoint, where NNN is a three digit number.) The first step is to load the recovery console. This could have been done from the “Safe Mode” boot menu option if grub was still active. However, since grub is blown-away, we’ll boot from the latest NexentaStor CD and select the recovery option from the menu.

Import the syspool

Then, we login as “root” (empty password.) From this “root shell” we can import the existing (disks connected to active controllers) syspool with the following command:

# zpool import -f syspool

Note the use of the “-f” card to force the import of the pool. Chances are, the pool will not have been “destroyed” or “exported” so zpool will “think” the pool belongs to another system (your boot system, not the rescue system). As a precaution, zpool assumes that the pool is still “in use” by the “other system” and the import is rejected to avoid “importing an imported pool” which would be completely catastrophic.

With the syspool imported, we need to mount the correct (latest) checkpointed filesystem as our boot reference for grub, destroy the local zfs.cache file (in case the pool disks have been moved, but still all there), update the boot archive to correspond to the mounted checkpoint and install grub to the disk(s) in the pool (i.e. each mirror member).

List the Checkpoints

# zfs list -r syspool

From the resulting list, we’ll pick our highest-numbered checkpoint; for the sake of this article let’s say it’s “rootfs-nmu-013” and mount it.

Mount the Checkpoint

# mkdir /tmp/syspool
# mount -F zfs syspool/rootfs-nmu-013 /tmp/syspool

Remove the ZPool Cache File

# cd /tmp/syspool/etc/zfs
# rm -f zpool.cache

Update the Boot Archive

# bootadm update-archive -R /tmp/syspool

Determine the Active Disks

# zpool status syspool

For the sake of this article, let’s say the syspool was a three-way mirror and the zpool status returned the following:

  pool: syspool
 state: ONLINE
  scan: resilvered 8.64M in 0h0m with 0 errors on Tue Nov 16 12:34:40 2010
        NAME           STATE     READ WRITE CKSUM
        syspool        ONLINE       0     0     0
          mirror-0     ONLINE       0     0     0
            c6t13d0s0  ONLINE       0     0     0
            c6t14d0s0  ONLINE       0     0     0
            c6t15d0s0  ONLINE       0     0     0

errors: No known data errors

This enumerates the three disk mirror as being composed of disks/slices c6t13d0s0, c6t14d0s0 and c6t15d0s0. We’ll use that information for the grub installation.

Install Grub to Each Mirror Disk

# cd /tmp/syspool/boot/grub
# installgrub -f -m stage[12] /dev/rdsk/c6t13d0s0
# installgrub -f -m stage[12] /dev/rdsk/c6t14d0s0
# installgrub -f -m stage[12] /dev/rdsk/c6t15d0s0

Unmount and Reboot

# umount /tmp/syspool
# sync
# reboot

Now, the system should be restored to a bootable configuration based on the selected system checkpoint. A similar procedure can be found on Nexenta’s site when using the “Safe Mode” boot option. If you follow that process, you’ll quickly encounter an error – likely intentional and meant to elicit a call to support for help. See if you can spot the step…


Short-Take: ZFS version ZPOOL Versions

November 15, 2010

As features are added to ZFS – the ZFS (filesystem) code may change and/or the underlying ZFS POOL code may change. When features are added, older versions of ZFS/ZPOOL will not be able to take advantage of these new features without the ZFS filesystem and/or pool being updated first.

Since ZFS filesystems exist inside of ZFS pools, the ZFS pool may need to be upgraded before a ZFS filesystem upgrade may take place. For instance, in ZFS pool version 24, support for system attributes was added to ZFS. To allow ZFS filesystems to take advantage of these new attributes, ZFS filesystem version 4 (or higher) is required. The proper order to upgrade would be to bring the ZFS pool up to at least version 24, and then upgrade the ZFS filesystem(s) as needed.

Systems running a newer version of ZFS (pool or filesystem) may “understand” an earlier version. However, older versions of ZFS will not be able to access ZFS streams from newer versions of ZFS.

For NexentaStor users, here are the current versions of the ZFS filesystem (see “zfs upgrade -v”):

---  --------------------------------------------------------
 1   Initial ZFS filesystem version
 2   Enhanced directory entries
 3   Case insensitive and File system unique identifier (FUID)
 4   userquota, groupquota properties
 5   System attributes

For NexentaStor users, here are the current versions of the ZFS pool (see “zpool upgrade -v”):

---  --------------------------------------------------------
 1   Initial ZFS version
 2   Ditto blocks (replicated metadata)
 3   Hot spares and double parity RAID-Z
 4   zpool history
 5   Compression using the gzip algorithm
 6   bootfs pool property
 7   Separate intent log devices
 8   Delegated administration
 9   refquota and refreservation properties
 10  Cache devices
 11  Improved scrub performance
 12  Snapshot properties
 13  snapused property
 14  passthrough-x aclinherit
 15  user/group space accounting
 16  stmf property support
 17  Triple-parity RAID-Z
 18  Snapshot user holds
 19  Log device removal
 20  Compression using zle (zero-length encoding)
 21  Deduplication
 22  Received properties
 23  Slim ZIL
 24  System attributes
 25  Improved scrub stats
 26  Improved snapshot deletion performance

As versions change, upgrading the ZFS pool and filesystem is possible using the respective upgrade command. To upgrade all imported ZFS pools, issue the following command as root:

zpool upgrade -a

Likewise, to upgrade the ZFS filesystem(s) inside the pool and all child filesystems, issue the following command as root:

zfs upgrade -r -a

The new ZFS features available to these pool and filesystem version(s) will now be available to the upgraded pools/filesystems.


Short-Take: iSCSI+Nexenta, Performance Notes

September 14, 2010

Here are a few performance tips for running iSCSI with NexentaStor in a Windows environment:

  1. When using the Windows iSCSI Software Initiator with some workloads, disabling the Nagle Algorithm on the Windows Server is sometimes recommended;
  2. Tuning TCP window and iSCSI parameters on each side of the connection can deliver better performance;
  3. VMware part of the equation? Adjusting the way VMware handles congestion events could be useful;
  4. On NexentaStor, disable the Nagle Algorithm with a value of “1” (default, 4095, enabled)

For storage applications where latency is a paramount issue, these hints just might help…