Asigra reporting “cannot allocate memory” during seed import

We have DS-Systems running on Linux and we connect the Windows Seed backups to a Windows 7/8.1 machine and then use CIFS to mount the Windows share to Linux. The command we use on Linux to mount the Windows share is:

mount -t cifs //<ipaddress of windows machine>/<sharename> -o username=administrator,password=xxxxxx /mnt/seed

We were importing some large backup sets with millions of files and started noticing “cannot allocate memory” errors during the seed import process. When the import would complete it would indicate that not all files were imported.

At first we thought this was an Asigra issue, but after much troubleshooting we found this was an issue with the Windows machine we were using and was related to using the CIFS protocol with Linux.

A sample link to the issue we were seeing is: http://linuxtecsun.blogspot.ca/2014/12/cifs-failed-to-allocate-memory.html

That link indicates to make the following changes on the Windows machine:

regedit:

HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\MemoryManagement\LargeSystemCache (set to 1)

HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters\Size (set to 3)

Alternatively, start Command Prompt in Admin Mode and execute the following:

reg add “HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management” /v “LargeSystemCache” /t REG_DWORD /d 1 /f

reg add “HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters” /v “Size” /t REG_DWORD /d 3 /f

Do one of the following for the settings to take effect:

Restart Windows

Restart the Server service via services.msc or from the Command Prompt run: ‘net stop lanmanserver’ and ‘net start lanmanserver’ – The server may automatically restart after stopping it.

After we made these changes the memory errors were resolved!

Asigra slow seed import

We recently discovered that Asigra DS-System v13.0.0.5 seems to have a serious problem with importing seed backups. This problem exposed itself as we attempted to import 5.5TB of seed data. We then performed additional testing by backing up a small Windows 2008 server. The seed backup was a little under 3GB. On v13.0.0.5 the seed import took 55 minutes. On the same infrastructure, the same server seed backup imported into a v12.2.1 DS-System in less than 3 minutes.

In addition we are also seeing the error “cannot allocate memory” during the seed import process even though we have tons of free RAM and disk space.

We have notified Asigra and they are attempting to reproduce the problem.

Update 12/4/2015

In testing, and working with Asigra, we have found that if you create the seed backup without using the metadata encryption option then the seed import speed is acceptable and imports quickly.

Update 12/8/2015

Asigra released DS-System v13.0.0.10 to address this issue. Testing shows it does indeed solve the speed issue. Thanks Asigra!

Zerto backup fails unexpectedly

We had a recent issue with Zerto backups that took some time to remedy. There was a combination of issues that exposed the problem, and here is a run down of what happened.

We had a customer with about 2TB of VM’s replicating via Zerto. We wanted to provide backup copies using the Zerto backup capability. Keep in mind Zerto is primarily a disaster recovery product and not a backup product (read more about that here: Zerto Backup Overview). The replication piece worked flawlessly, but we were trying to create longer-term backups of virtual machines using Zerto’s backup mechanism which is different from Zerto replication.

Zerto performs a backup by writing all of the VM’s within a VPG to a disk target. It’s a full copy, not incremental, so it’s a large backup every time it runs, especially if it’s a VPG holding a lot of VMs. We originally used a 1Gigabit network to transfer this data, but quickly learned we need to upgrade to 10Gigabit to accommodate these frequent large transfers.

However, we found that most of the time the backup would randomly fail. The failure message was:

“Backup Protection Group ‘VPG Name’. Failure. Failed: Either a user or the system aborted the job.”

To resolve the issue we had opened up several support cases with Zerto, upgraded from version 3.5 to v4, implemented 10Gigabit, put the backup repository directly on the Zerto Manager server.

After opening several cases with Zerto we finally had a Zerto support engineer thoroughly review the Zerto logs. They found there were frequent disconnection events. With this information we explored the site-to-site VPN configuration and found there were minor mismatches in the IPSEC configurations on each side of the VPN which were causing very brief disconnections. These disconnections were causing the backup to fail. Lesson learned: It’s important to ensure the VPN end-points are 100% the same. We use VMware vShield to establish the VPN connections and vShield doesn’t provide a lot of flexibility to change VPN settings, so we had to change the customer’s VPN configuration to match the vShield configuration.

Even though we seemed to have solved the issue by fixing the VPN settings, we asked Zerto if there was any way to make sure the backup process ran even if there was a connection problem. They shared with us a tidbit of information that has enabled us to achieve 100% backup success:

There is a tweak that can be implemented in the ZVM which will allow the backup to continue in the event of a disconnection, but there’s a drawback to this in that the ZVM’s will remain disconnected until the backup completes. As of now, there’s no way to both let the backup continue and the ZVM’s reconnect. So there is a drawback, but for this customer it was acceptable to risk a window of time that replication would stop to make a good backup. In our case we made the backup on Sunday when RPO wasn’t as critical, and even then the replication only halts if there is a disconnection between the sites which became even more rare since we fixed the VPN configuration.

The tweak:

On the Recovery (target) ZVM, open the file C:\Program Files (x86)\Zerto\Zerto Virtual Replication\tweaks.txt (may be in another drive, depending on install)
In that file, insert the following string (on a new line if the file is not empty)
t_skipClearBlockingLine = 1
Save and close the file, then restart the Zerto Virtual Manager and Zerto Virtual Backup Appliance services

Now, when you run a backup, either scheduled or manual, any ZVM <-> ZVM disconnection events should not cause the backup to stop.

I hope this helps someone else!

Zerto Backup Overview

Zerto is primarily a disaster recovery solution that relies on a relatively short-term journal that retains data for a maximum of 5 days (at great expense in disk storage). Many Zerto installations only have a 4-hour journal to minimize the storage needed for the journal. Zerto is a great disaster recovery solution, but not as great as a backup solution.  Many customers will augment Zerto with a backup solution for long-term retention of past data.

Long-term retention is the ability to go back to previous versions of data, which is often needed for compliance reasons. Think about the ability to go back weeks, months, and even years to past versions of data. Even if not driven by compliance, the need to go back in time to view past versions of data is very useful in situations such as:

  • Cryptolocker type ransom-ware corrupts your data and is replicated to the DR site
  • Legal discovery – for example, reviewing email systems as they were months or even years ago.
  • Inadvertent overwriting of critical data such as a report that is updated quarterly. Clicking “Save” instead as “Save As” is a good example of how this can happen.
  • Unexpected deletion of data that takes time to recognize.

For reference and further clarification, check out the differences between disaster recovery, backup and business continuity.

Even though Zerto is primarily a disaster recovery product, it does have some backup functions.

Zerto backup functionality involves making an entire copy of all of the VM’s within a VPG. We sometimes break up VPG’s with the goal to facilitate efficient backups. One big VPG can result in making one big backup which can take many hours (or days) to complete. Since it’s an entire copy of the VPG it can take a significant amount of time and storage space to store the copy. Each backup is a full backup and currently no incremental/differential backup capability exists within Zerto.

It is also advisable to write the backups to a location which support de-duplication, such as Windows 2012 Server. It still takes time to write the backup, but the de-duplication will dramatically lower the required storage footprint for backing up Zerto VPG’s. Without de-duplication on the backup storage you will see a large amount of storage consumed by each full backup of the VPGs.

Zerto supports the typical grandfather-father-son backup with daily, weekly and monthly backups for 1 year. Zerto currently does not support backups past 1 year, so even with Zerto backups, the long-term retention of data is not as good as with other products designed to be backup products. However, Zerto really shines as a disaster recovery tool when you need quick access to the latest version of your servers. It’s backup capabilities will get better with time.

 

 

 

 

The difference between disaster recovery, backup and business continuity

I sometimes see words like backup and disaster recovery used interchangeably, and sometimes in the wrong context. I see a customers asking for a DR solution when they need backup and DR. Some refer to it in the industry as BDR (Backup & Disaster Recovery).

So what’s the difference? Why should you care?

Disaster Recovery

Disaster recovery is about restoring critical IT functions quickly after a disaster. Disasters can be small from a critical server failing, to natural disasters like fire, flooding, tornado, hurricane to manmade disasters such as construction accidents, theft, sabotage, chemical spills, that may render your entire site unusable. The idea of DR is to restore critical IT services as quickly as possible after a disaster. Obviously this can encompass much more than just data recovery. A comprehensive DR plan might include alternate sites, spare hardware, etc.

Backup

Backup, on the other hand, can include the ability to perform a rapid recovery – yes Disaster Recovery, but it can also provide you access to the past history of your backed up data. That is a big distinction between backup and disaster recovery. There are some really great disaster recovery products that provide a very quick recovery to a very recent copy of a server in the case of disaster, but were never designed to provide data even 2 weeks ago, much less 6 months ago or even years ago.

In addition to restoring the most recent file, backup allows access to older, past versions of files. Older versions of files allow to recover from data loss that occurred in the past, but is noticed in the present. A cryptolocker ransomware type infection is a good example in that the latest backups may be of infected files and a restore is required from before the infection. It’s also very easy to bring up a monthly report in Word and select “Save” instead of “Save As”, overwriting the original document. Without keeping copies of past versions, we could potentially lose valuable data.

Some organizations are mandated by law to keep copies of their older data as well. Think medical providers who need to keep past patient data for years.

Backup data can be current data used for DR, but it’s also the past versions of data and being able to reproduce data as it was back to a certain point in time can be of enormous value.

Business Continuity

Business Continuity is generally defined as the process by which an organization can continue essential business functions despite a disaster. A comprehensive business continuity plan is far more than just restoring servers and data, and often includes things that are not IT related at all.

The business operation needs of every organization can be different. Some business are highly dependent on phone service to take calls from customers for instance, while some businesses require specialized equipment that is not easily replaced, or replaced quickly. Who are the critical employees and what functions do they perform? Where will employees work if the office is unavailable? There are many, many questions to ask in order to create an effective business continuity plan, and data recovery is only one of many areas of concern.

Asigra BLM Archiving – Align the value of your data with the cost to protect it

Years ago, we treated all data as being equal. All data originated on one type of storage and stayed there until it was deleted. We now understand that not all data is created equal. Some types of data are more important than others, or accessed more frequently than others. Backup Lifecycle Management (BLM), defines the BLM concept where data is created on one storage system, then migrated to less expensive storage systems as it ages.

Asigra Backup Tiers

BLM-graphic

For example:

Data that is 2 minutes old is highly valued.
Data that is 2 months old may be of interest but is not as highly valued.
Data that is 2 years old may be needed for records but it is not critical to the daily functioning of the company.
DS-System – Primary Storage-Business-Critical Operational Data

Business Critical Operation Data contains the files, databases, email systems, etc., that are needed for operations on a day-to-day basis. All data that is critical to business operations data should be stored in the DS-System Tier.

BLM Archiver – Policy based retention of older data

Large file servers or other large repositories of potentially older data can be moved to BLM, Cost savings are the primary benefit by allowing storage of older data and automatic retention policies that move aged data into the lower cost tier. BLM Archiver can also be leveraged to provide storage of past generations of data while keeping the most recent version in business critical DS-System.

Managecast will help with analyzing your data to determine a protection method to best suit your recovery requirements and budget. There are many options to protect business data by strategically identifying the value and aligning the cost to protect it.

BLM Cloud Storage – For Low-Cost, Rarely Retrieved Files

Typically for files older than 1 year, BLM Cloud Storage is a method to cost effectively protect large data sets that are still needed for reference, compliance, and infrequent restores.

Files older than a specified age can be selected to move to long-term cloud storage and are generally grouped in large chucks from 250GB on up to multiple terabytes and then copied to long-term archive on disk.

Customers can utilize Amazon S3 cloud storage or use Managecast Enterprise Cloud Storage