StarWind Virtual SAN Working with StarWind LSFS Snapshots in ESXi

Transcription

1 One Stop Virtualization Shop StarWind Virtual SAN Working with StarWind LSFS Snapshots in ESXi MARCH 2017 TECHNICAL PAPER

2 Trademarks StarWind, StarWind Software and the StarWind and the StarWind Software logos are registered trademarks of StarWind Software. StarWind LSFS is a trademark of StarWind Software which may be registered in some jurisdictions. All other trademarks are owned by their respective owners. Changes The material in this document is for information only and is subject to change without notice. While reasonable efforts have been made in the preparation of this document to assure its accuracy, StarWind Software assumes no liability resulting from errors or omissions in this document, or from the use of the information contained herein. StarWind Software reserves the right to make changes in the product design without reservation and without notification to its users. Technical Support and Services If you have questions about installing or using this software, check this and other documents first - you will find answers to most of your questions on the Technical Papers webpage or in StarWind Forum. If you need further assistance, please contact us. Copyright StarWind Software Inc. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written consent of StarWind Software. In 2016, Gartner named StarWind Cool Vendor for Compute Platforms. Gartner does not endorse any vendor, product or service depicted in its research publications, and does not advise technology users to select only those vendors with the highest ratings or other designation. Gartner research publications consist of the opinions of Gartner's research organization and should not be construed as statements of fact. Gartner disclaims all warranties, expressed or implied, with respect to this research, including any warranties of merchantability or fitness for a particular purpose. About StarWind StarWind is a pioneer in virtualization and a company that participated in the development of this technology from its earliest days. Now the company is among the leading vendors of software and hardware hyper-converged solutions. The company s core product is the years-proven StarWind Virtual SAN, which allows SMB and ROBO to benefit from cost-efficient hyperconverged IT infrastructure. Having earned a reputation of reliability, StarWind created a hardware product line and is actively tapping into hyperconverged and storage appliances market. In 2016, Gartner named StarWind Cool Vendor for Compute Platforms following the success and popularity of StarWind HyperConverged Appliance. StarWind partners with world-known companies: Microsoft, VMware, Veeam, Intel, Dell, Mellanox, Citrix, Western Digital, etc. TECHNICAL PAPER 2

3 Contents Introduction... 4 Creating a Snapshot... 5 Snapshot mounting in StarWind Console... 7 Mounting the snapshot to the ESXi host Mounting the snapshot with the existing signature Mounting the snapshot with a new signature Mounting the snapshot with full formatting Working with multiple snapshots Conclusion Contacts TECHNICAL PAPER 3

4 Introduction This technical paper describes how to successfully mount the StarWind LSFS snapshot in the ESXi. Snapshot mounting may come in handy when you need to restore the data that has been lost or deleted from the device. By default, all LSFS snapshots are mounted only in read-only mode. When mounting the snapshot in StarWind management console, a new separate StarWind device with a new Target is created. Having connected to the ESXi host, the snapshot tries to write its "signature" to the disc, but fails to do it, being read-only. As a result, an error occurs, and the snapshot doesn t get mounted. To tackle this issue, LSFS has a pseudo read only - mode: a small WB cache that is never flushed. When the snapshot is created, the console sends IsEsxCompatibleMode: Yes", and the device rises to the ESXi compatible mode. This paper will cover three basic mounting scenarios: turning off the original device and keeping the existing signature; assigning a new signature (UUID); formatting the disk. This guide is intended for experienced system administrators and IT professionals who would like to configure StarWind Virtual SAN solution. It provides detailed instructions on how to create and mount the LSFS snapshots in the ESXi. Please note that this document assumes that you ve got an LSFS device created. If you don t know how to do it, consult the StarWind Virtual SAN built-in Help or refer to the corresponding guide from the technical papers section on StarWind website. A full set of up-to-date technical documentation can always be found here or by pressing the Help button in the StarWind Management Console. For any technical inquiries, please visit our online community, Frequently Asked Questions page, or use the support form to contact our technical support department. TECHNICAL PAPER 4

5 Creating a Snapshot PLEASE NOTE: a snapshot can be taken only after the original StarWind device is connected to the client (hypervisor) as a datastore. 1. Launch StarWind Management Console. Right click LSFS device you want and select Snapshot Manager from the pop-up menu. 2. Click Create Snapshot button. TECHNICAL PAPER 5

6 3. Enter the snapshot name or leave it default. Click Create. TECHNICAL PAPER 6

7 Snapshot mounting in StarWind Console 1. Select the snapshot and click Mount Snapshot button. 2. Leave the default cache settings and click Next. TECHNICAL PAPER 7

8 3. Leave the default settings and click Next. 4. Click Create. 5. Click Next. TECHNICAL PAPER 8

9 6. Click Close after the device is created. 3.1 The status of the selected snapshot is changed to Mounted. TECHNICAL PAPER 9

10 3.2 The new snapshot is available on the list of StarWind devices. TECHNICAL PAPER 10

11 Mounting the snapshot to the ESXi host Mounting the snapshot with the existing signature PLEASE NOTE: this option works only when the snapshot is directly connected to the ESXi host. So far, the snapshot cannot be properly mounted in the vcenter on the ESXi host due to the VMware known issue. 1. Right click the original device and Unmount it from the ESXi host. 2. Click Add Storage. TECHNICAL PAPER 11

12 3. Select the LUN. The name of the original device the snapshot was taken from is displayed in the VMFS Label column. 4. Select Keep the existing signature. TECHNICAL PAPER 12

13 5. Click Finish. 6. The snapshot is successfully created. WARNING: Once you have finished working with the snapshot, you need to unmount it from the ESXi host. DO NOT REMOVE THE SNAPSHOT! The delete operation will overwrite the device signature with zeros, and the snapshot will be no longer available for re-mounting! Mounting the snapshot with a new signature When mounting the snapshot with a new signature, ESXi assigns it a new UUIDand a new name and mounts it as a separate independent Datastore. The default format of the new name is snap-snapid-oldlabel, where oldlabel is the name of the original device. 1. Run the wizard and click Add Storage. TECHNICAL PAPER 13

14 2. Select the LUN. The name of the original device the snapshot was taken from is displayed in the VMFS Label column. 3. Select Assign a new signature. TECHNICAL PAPER 14

15 4. The last page shows the new UUID the ESXi assigned to the mounted snapshot, which now is a separate Datastore. Click Finish. WARNING: Once you have finished working with the snapshot, you need to unmount it from the ESXi host. DO NOT REMOVE THE SNAPSHOT! The delete operation will overwrite the device signature with zeros, and the snapshot will be no longer available for re-mounting! The second option you can unmount the snapshot from the ESXi host in Starwind Console. To do this, right click the target and select Force remove Target from the pop-up menu. Mounting the snapshot with full formatting Format the disk option is available, but it makes little sense since the snapshots are ReadOnly. If you select this option, the ESXi will try to remove the file system from the ReadOnly snapshot, which will lead to an access error. Working with multiple snapshots Prior to mounting the snapshot in the ESXi, it must be mounted in the StarWind management console as a separate Target Device. The above-described interaction aspects of the ESXi and snapshots don t allow mounting several snapshots of the Starwind device and connecting them to the ESXi host. Therefore, only one StarWind snapshot must be mounted for successful work with the ESXi! The HA LSFS works in the same way as a usual LSFS, but one more condition is added: in case the already mounted snapshot resides on one of the StarWind nodes, it cannot be mounted on other nodes! TECHNICAL PAPER 15

16 Conclusion Keeping the existing signature and assigning a new one are two basic scenarios that allow successful mounting of the StarWind snapshot in the ESXi using the Add Storage wizard in the vsphere client. The first option, keeping the existing signature, requires the original device being unmounted from the ESXi host since connecting the snapshot with the same UUID can cause all kinds of issues. As you have seen, once the initial datastore is turned off, the mounted snapshot with the same signature can be brought online. The second option, assigning a new signature, allows creating a separate datastore as the hypervisor assigns it new technical identifiers different from those of the initial one. To avoid all kinds of errors, it is highly recommended to mount only one snapshot of the StarWind device in the ESXi. In case of the HA LSFS, the snapshot can be mounted only on one of the nodes running the StarWind service. TECHNICAL PAPER 16

17 Contacts US Headquarters EMEA and APAC (UK) (Germany) (France) (Russian Federation and CIS) Customer Support Portal: Support Forum: Sales: General Information: StarWind Software, Inc. 35 Village Rd., Suite 100, Middleton, MA USA , StarWind Software Inc. All rights reserved. TECHNICAL PAPER 17